ASTM D7452-24

Standard Test Method for Evaluation of the Load Carrying Properties of Lubricants Used for Final Drive Axles, Under Conditions of High Speed and Shock Loading

SIGNIFICANCE AND USE
5.1 Final drive axles are often subjected to severe service where they encounter high speed shock torque conditions, characterized by sudden accelerations and decelerations. This severe service can lead to scoring distress on the ring gear and pinion surface. This test method measures anti-scoring properties of final drive lubricants.  
5.2 This test method is used or referred to in the following documents:  
5.2.1 American Petroleum Institute (API) Publication 1560.7  
5.2.2 SAE J308 and SAE J2360.
SCOPE
1.1 This test method covers the determination of the anti-scoring properties of final drive axle lubricating oils when subjected to high-speed and shock conditions. This test method is commonly referred to as the L-42 test.2  
1.2 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard.  
1.2.1 Exceptions—SI units are provided for all parameters except where there is no direct equivalent such as the units for screw threads, National Pipe Threads/diameters, tubing size, and single source equipment suppliers.  
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. Specific warning information is given in Sections 4 and 7.  
1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

General Information

• Status: Published
• Publication Date: 29-Feb-2024
• ICS: 75.100 - Lubricants, industrial oils and related products
• Technical Committee: D02 - Petroleum Products, Liquid Fuels, and Lubricants
• Drafting Committee: D02.B0.03 - Automotive Gear Lubricants & Fluids

Relations

• Replaces: ASTM D7452-22 - Standard Test Method for Evaluation of the Load Carrying Properties of Lubricants Used for Final Drive Axles, Under Conditions of High Speed and Shock Loading
• Effective Date: 01-Mar-2024
• Referred By: ASTM D7450-19 - Standard Specification for Performance of Rear Axle Gear Lubricants Intended for API Category GL-5 Service
• Effective Date: 01-Mar-2024

Overview

ASTM D7452-24 is the Standard Test Method for the Evaluation of the Load Carrying Properties of Lubricants Used for Final Drive Axles, Under Conditions of High Speed and Shock Loading. This standard, developed by ASTM International, defines laboratory procedures-commonly referred to as the L-42 test-to assess the anti-scoring characteristics of lubricating oils intended for use in final drive axles. These axles are regularly exposed to severe operating conditions, including high-speed torque shocks stemming from rapid acceleration or deceleration events, where gear lubrication must prevent surface distress such as scoring on ring and pinion gears.

Compliance with ASTM D7452-24 enables manufacturers, lubricant formulators, and testing laboratories to ensure high-performance lubricant validation, contributing to longer axle component life, improved performance under tough environments, and alignment with international and industry-specific requirements.

Key Topics

• Assessment of Anti-Scoring Properties: The standard centers on evaluating a lubricant’s ability to protect hypoid gear surfaces in rear axles under simulated high-speed and shock loading.
• Test Method (L-42): Utilizes a carefully defined laboratory procedure involving a light duty hypoid rear axle (Dana Model 44) and controlled dynamometer-driven cycles to subject gears to shock torque events.
• Laboratory Calibration and Control: Recommends the use of reference oils and calibration processes, often administered by the ASTM Test Monitoring Center (TMC), to ensure consistent and reliable results across participating laboratories.
• Statistical Assurance: Details procedures for test stand calibration, quality assurance via reference oils, and ensures statistical comparability according to strict industry requirements.
• Safety and Good Laboratory Practice: The method emphasizes implementing appropriate safety, health, and environmental protocols, as well as compliance with regulatory frameworks.

Applications

ASTM D7452-24 is highly relevant for professionals and organizations engaged in the field of automotive lubricant development, quality control, and compliance testing. Notable applications include:

• Product Development: Supporting formulation and iterative improvement of axle lubricants for severe duty vehicles, including commercial trucks, off-road vehicles, and passenger cars that require high resistance to gear scoring.
• Performance Validation: Used by manufacturers, oil marketers, and additive companies to substantiate product claims related to extreme pressure and anti-scoring performance, serving as a basis for product certifications.
• Industry Approval and Specification: Frequently referenced in procurement and technical approval documents such as the American Petroleum Institute (API) Publication 1560.7 and SAE J308/J2360, forming part of industry benchmarks for gear oil quality.
• International Compliance: Recognized for ensuring that lubricants meet globally harmonized standards, minimizing technical barriers to trade in axle lubricants.

Related Standards

ASTM D7452-24 interacts with several important standards and specifications designed for gear oils and axle lubricants, including:

• API Publication 1560.7: Sets performance requirements for automotive axle lubricants and incorporates ASTM D7452-24 results for anti-scoring qualifications.
• SAE J308: Classifies gear lubricants by performance characteristics and viscosity grades; often requires conformance to ASTM D7452-24.
• SAE J2360: Establishes requirements for multipurpose gear lubricants, including lab test data from the L-42 method.
• ASTM D235: Specification for mineral spirits, referenced for cleaning processes in laboratory testing.
• ASTM E29: Practice for using significant digits in test data to determine specification conformance.

By adhering to ASTM D7452-24, stakeholders ensure that axle lubrication products meet rigorous automotive industry performance standards, ultimately supporting safe, durable, and efficient operation in vehicles exposed to challenging torque and speed conditions.

Standards Content (Sample)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: D7452 − 24
Standard Test Method for
Evaluation of the Load Carrying Properties of Lubricants
Used for Final Drive Axles, Under Conditions of High Speed
and Shock Loading
This standard is issued under the fixed designation D7452; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
INTRODUCTION
Portions of this test method are written for use by laboratories that make use of ASTM Test
Monitoring Center (TMC) services (see Annex A1 – Annex A4).
The TMC provides reference oils, and engineering and statistical services to laboratories that desire
to produce test results that are statistically similar to those produced by laboratories previously
calibrated by the TMC.
In general, the Test Purchaser decides if a calibrated test stand is to be used. Organizations such as
the American Chemistry Council require that a laboratory use the TMC services as part of their test
registration process. In addition, the American Petroleum Institute and the Gear Lubricant Review
Committee of the Lubricant Review Institute (SAE International) require that a laboratory use the
TMC services in seeking qualification of oils against their specifications.
The advantage of using the TMC services to calibrate test stands is that the test laboratory (and
hence the Test Purchaser) has an assurance that the test stand was operating at the proper level of test
severity. It should also be borne in mind that results obtained in a non-calibrated test stand may not
be the same as those obtained in a test stand participating in the ASTM TMC services process.
Laboratories that choose not to use the TMC services may simply disregard these portions.
1. Scope* screw threads, National Pipe Threads/diameters, tubing size,
and single source equipment suppliers.
1.1 This test method covers the determination of the anti-
1.3 This standard does not purport to address all of the
scoring properties of final drive axle lubricating oils when
safety concerns, if any, associated with its use. It is the
subjected to high-speed and shock conditions. This test method
responsibility of the user of this standard to establish appro-
is commonly referred to as the L-42 test.
priate safety, health, and environmental practices and deter-
1.2 The values stated in inch-pound units are to be regarded
mine the applicability of regulatory limitations prior to use.
as standard. The values given in parentheses are mathematical
Specific warning information is given in Sections 4 and 7.
conversions to SI units that are provided for information only
1.4 This international standard was developed in accor-
and are not considered standard.
dance with internationally recognized principles on standard-
1.2.1 Exceptions—SI units are provided for all parameters
ization established in the Decision on Principles for the
except where there is no direct equivalent such as the units for
Development of International Standards, Guides and Recom-
mendations issued by the World Trade Organization Technical
Barriers to Trade (TBT) Committee.
This test method is under the jurisdiction of ASTM Committee D02 on
Petroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility of
2. Referenced Documents
Subcommittee D02.B0.03 on Automotive Gear Lubricants & Fluids.
Current edition approved March 1, 2024. Published March 2024. Originally
2.1 ASTM Standards:
approved in 2008. Last previous edition approved in 2022 as D7452 – 22. DOI:
D235 Specification for Mineral Spirits (Petroleum Spirits)
10.1520/D7452-24.
Until the next revision of this test method, the ASTM Test Monitoring Center
(TMC) will update changes in this test method by means of information letters.
Information letters may be obtained from the ASTM Test Monitoring Center, 203 For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Armstrong Drive, Freeport, PA 16229, Attention: Director. This edition incorporates contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
revisions in all information Letters through No. 23-1. The TMC is also a source of Standards volume information, refer to the standard’s Document Summary page on
reference oils. the ASTM website.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D7452 − 24
(Hydrocarbon Dry Cleaning Solvent) 5.2.1 American Petroleum Institute (API) Publication
E29 Practice for Using Significant Digits in Test Data to 1560.
Determine Conformance with Specifications 5.2.2 SAE J308 and SAE J2360.
2.2 Society of Automotive Engineers Standards:
6. Apparatus
SAE J308 Information Report on Axle and Manual Trans-
6.1 This test method provides a description of essential
mission Lubricants
apparatus features, including mandatory equipment type and
SAE J2360 Lubricating Oil, Gear Multipurpose (Metric)
performance specifications where established.
Military Use
6.2 Test Axle—The test unit consists of a Dana model 44
3. Terminology
rear axle, 45 to 11 (4.09) ratio, and uncoated gears. (Dana
ASTM part number 044AA100-1. See 10.1.)
3.1 Definitions of Terms Specific to This Standard:
3.1.1 coast side, n—the convex side of the pinion and the
6.3 Cover Plate—Modify the rear cover plate of the test unit
concave side of the ring gear which are in contact during
to provide an inspection port and thermocouple fitting. Locate
deceleration in a forward gear.
the thermocouple fitting by using the locating fixture shown in
ASTM Distress Rating Manual 21 1
Fig. A6.1. An optional ⁄4 in. NPT (National Pipe Thread) drain
3.1.2 drive side, n—the concave side of the pinion and the fitting may be added.
convex side of the ring gear which are in contact during
6.4 Axle Shaft Assemble—Use a Ford Axle shaft assembly,
acceleration in a forward gear. 6
(Dana Part No. 26762-14X ) or equivalent with this test
ASTM Distress Rating Manual 21
method.
3.1.3 scoring, n—on the ring and the pinion gear teeth, the
6.5 Hinge Plate Stand Assembly—Mount and secure the test
displacement of metal by local momentary welding from the
unit in place on the hinge plate assembly, see Figs. A6.6-A6.9.
gear tooth, resulting in the development of a matt, or frosted
6.6 Temperature Control System—The temperature control
dull surface.
apparatus consists of a thermocouple, a temperature recording
ASTM Distress Rating Manual 21
system, temperature controller and a cooling system that is able
to maintain lubricant temperature at specified conditions.
4. Summary of Test Method
6.6.1 Thermocouple—Install the thermocouple such that the
4.1 Charge a specially prepared light duty hypoid rear axle
thermocouple tip is flush with the cover plate lip by placing the
(Dana Model 44 ASTM Part No. 044AA100-1) with the
cover plate face on a flat surface and inserting the thermo-
lubricant sample to be tested (see 10.1). Mount the axle
couple into the cover plate until the thermocouple tip is flush
between two load absorbing dynamometers which are driven
with the flat surface. For recording and control of the test
with a V-8 gasoline engine through a manual transmission.
lubricant temperature, use a ⁄8 in. (3.2 mm) diameter J or K
4.2 Condition the test axle with light loads at different
type closed tip style thermocouple.
speed, torque and temperature conditions on both the drive and
6.6.2 Temperature Recording System—Throughout the test,
coast sides of the gears. (Warning—High-speed rotating
ensure the temperature recording system records the tempera-
equipment, electrical shock, high-temperature surfaces.) After
ture of the test oil at a minimum frequency of 1 Hz.
conditioning, subject the test axle to high speed and shock
6.6.3 Temperature Controller—Proportional-Integral-
loadings at higher temperatures.
Derivative (PID) type; percent output adjustable.
6.6.4 Axle Cooling—Use three spray nozzles to distribute
4.3 Rate the drive and coast side of the pinion and ring gears
water over the cover plate and axle housing as shown in Fig.
at the end of test (EOT) for scoring distress.
A6.2. Actuate the water control valve by the temperature PID
control system.
5. Significance and Use
6.6.4.1 Depending on how the system is plumbed, use spray
5.1 Final drive axles are often subjected to severe service
nozzles in any combination of the following part numbers:
where they encounter high speed shock torque conditions,
Straight Male NPT (Part No. 3/8GG-SS22), 90° Male NPT
characterized by sudden accelerations and decelerations. This
(Part No. 3/8GGA-SS22), Straight Female NPT (Part No.
severe service can lead to scoring distress on the ring gear and
8,9
3/8G-SS22), and 90° Female NPT (Part No. 3/8GA-SS22).
pinion surface. This test method measures anti-scoring prop-
6.6.4.2 Use a single control valve to control the cooling
erties of final drive lubricants.
water supply. The control shall be a ⁄2 in. (12.7 mm) two-way,
5.2 This test method is used or referred to in the following
documents:
API Publication 1560, Lubricant Service Designations for Automotive Manual
Transmissions, Manual Transaxles, and Axles, American Petroleum Institute,
Washington, DC.
4 8
Available from Society of Automotive Engineers (SAE), 400 Commonwealth The sole source supply of the apparatus known to the committee at this time is
Dr., Warrendale, PA 15096-0001, http://www.sae.org. Spray Systems Company, and can be purchased through E. I. Pfaff Company, 3443
Formerly known as CRC Rating Manual, No. 21. Available from the ASTM Edwards Road, Suite D, Cincinnati, OH 45208.
website, www.astm.org, ASTM Stock No. TMCMNL21. If you are aware of alternative suppliers, please provide this information to
Parts and Model 44 Maintenance Manual available from Dana Corporation, ASTM International Headquarters. Your comments will receive careful consider-
P.O. Box 2424, Fort Wayne, IN 46801. ation at a meeting of the responsible technical committee, which you may attend.
D7452 − 24
TABLE 1 Recommended Power Train Replacement Parts List
C linear trim, air to close, Research Control valve. Use a single
PID loop to maintain the axle lubricant temperature control for Parts Part Number
both the Standard and Canadian version test. A separate PID Ramjet Engine Includes ECM 12495515
Five Speed Transmission 15747134 or
loop control for each version is not permitted. See Annex A5.
3 1
6.6.4.3 Use only ⁄8 in. or ⁄2 in. (9.5 mm or 12.7 mm) line
Bell Housing 15998496
material to the spray nozzles. Clutch Assembly 15002591
Throw Out Bearing 15705563
6.6.4.4 Use a minimum supply water pressure of 25 psig
Dip Stick 10190942
(172 kPa) to the control valve.
Dip Stick Tube 12552920
6.6.4.5 Use an axle containment box as shown in Fig. Flywheel 10105832
Flywheel Bolt (6 req.) 12337973
A6.10. The purpose is to contain water.
Pilot Bearing 14061685
6.6.4.6 Use a locating pin or stop block as an indexing
Master Cylinder 15727261
Actuating Cylinder 15046288
device to ensure that all subsequent axle installations are
Pulley, Water Pump 14023155
consistently installed perpendicular with the axle housing
Pulley, Crankshaft 14023147
cover to engine and transmission drive-shaft centerline.
Belt 9433720
Starter 10496873
6.7 Torque Meter—Include in the test equipment a torque
Engine Control Unit 12489488
meter installed in the drive shaft (see Figs. A6.3-A6.5) to
Throttle Body from 2000 Corvette. 17113669
Throttle Body TPS Connector P/N 12116247
measure the torque applied to the pinion. Install a Himmelstein
Throttle Body Actuator Motor Connector P/N 12167121
inline torque meter Model numbers MCRT28061T(1-4) or
K&N Inlet Air Filter P/N RD6020
9,10
MCRT2661TN(1-4) without a foot mount and a range of
10 000 lb-in. (1130 N·m) shall be installed to measure pinion
torque. Additional suffix letters only indicate allowable op-
required to fabricate the shafts. Ensure the shafts are dynami-
tions.
cally (spin) balanced and strong enough to handle torques up to
6.8 Signal Conditioning—Use a Himmelstein Models 701
2100 lbf-ft (2847 N·m). Use an operating angle of 0° 6 0.5°.
or 711 strain gage conditioner for signal conditioning. Set the
6.13 Power Train—The power train consists of a gasoline
low pass cut-off frequency at 10 Hz.
powered V-8 GM performance Ramjet 5.7 L marine engine
6.9 Digital Data Acquisition System—System requires ca-
coupled with a five speed manual transmission capable of
pability of measuring a minimum of five channels at sampling
supplying specified shock loading torques. The engine and
frequencies outlined in Section 10.
transmission operating angle shall be 0° 6 0.5°.
6.9.1 Do not use hardware or software filtering for the
6.13.1 All recommended replacement parts are available
pinion torque channel during data acquisition periods of the
through local General Motors dealers. A list of these replace-
test.
ment parts are shown in Table 1. Do not make modifications to
6.10 Dynamometers—Two axle dynamometers (Midwest the engine that would affect the engines factory displacement
9,11
Dynamatic, Model 3232) with suitable control equipment
or compression ratio.
capable of maintaining specified test conditions.
6.14 Drive Shaft—Welded steel tubing, 3.5 in. 6 0.2 in.
6.11 Engine Speed Control—System requires a device to
(90 mm 6 5.1 mm) outside diameter, 0.095 in. 6 0.005 in.
maintain steady state conditions and also provide adjustable (2.41 mm 6 0.13 mm) wall thickness, 34.5 in. 6 1 in.
throttle acceleration and deceleration rates to attain specified
(880 mm 6 25 mm) long from center weld to center weld. (See
shock loading torques. Figs. A6.3-A6.5.) Dynamically (spin) balance the drive shaft
6.11.1 Throttle Controller System—Use a Foxboro/Jordan
and torque meter. The operating angle shall be 0° 6 0.5°.
9,12 13
Controller, Model AD7530. Use a power transformer from 6.14.1 Transmission U-Joint—(Spicer 5-178X) or Neapco
Acme Electric Corp. PN T-1-81058 or equivalent, primary
2-1435
volts 120X240, secondary volts (120 V primary by 240 V 6.14.2 Pinion U-Joint—(Spicer 5-153X).
secondary), 16/32 (13 mm) center tap, 0.500 kVA (0.5 kW) in
6.14.3 Flange Yoke—Connects transmission yoke through
conjunction with the Foxboro/Jordan Controller. u-joint to drive shaft.
6.14.4 Pinion Drive Shaft Slip Yoke—Connects the drive
6.12 Connecting Shafts—Use connecting shafts of equal
shaft through the u-joint to the axle yoke.
length 61 in. (25.4 mm) and less than 30 in. (762 mm) long
6.14.5 Flange Adaptor—Manufacture flange adapter to
from flange face to flange face. Use a tubing diameter of 3.5 in.
specifications in Figs. A6.4 and A6.5.
6 0.2 in. (88.9 mm 6 5.1 mm) OD, with a wall thickness of
0.095 in. 6 0.005 in. (2.41 mm 6 0.13 mm) if tubing is 6.15 Spring Plate—Manufacture spring plates to specifica-
tion as shown in Fig. A6.8.
6.16 Spring Plate Rod Connection—Mount a rod connect-
The sole source supply of the apparatus known to the committee at this time
ing the spring plate to the gear stand using ⁄2 in. (13 mm)
is S. Himmelstein and Company, 2490 Pembroke Avenue, Hoffman Estates, IL
spherical rod ends. See Figs. A6.6 and A6.7.
60195.
Available from Dyne Systems, P.O. Box 18 W209 N17391 Industrial Drive,
Jackson, WI 53037.
12 13
Available from Fox/Jordan, Inc., 5607 West Douglas Avenue, Milwaukee, WI Available from any local drive shaft supplier.
53218. Available from Neapco, LLC, 6735 Haggerty Rd., Belleville, MI 48111.
D7452 − 24
7. Reagents and Materials 8.2.14 Install test unit on stand with pinion and axle shaft
center lines horizontal. The operating angle shall be 0° 6 0.5°.
7.1 Sealing Compound—Where necessary, use Permatex
After installing the axle, ensure that the hinge plate assembly is
No. 2 or equivalent.
free.
7.2 Cleaning Solvent—Use solvent meeting ASTM D235
8.2.15 Connect the dynamometers and drive shaft to the test
Type II, Class C requirements for Aromatic Content (0 to 2) %
unit.
by volume, Flash Point (142 °F ⁄61 °C, min) and Color (not
darker than +25 on Saybolt Scale or 25 on Pt-Co Scale).
9. Calibration and Standardization
(Warning—Health hazard, combustible.) Obtain a Certificate
9.1 Annex A2 describes general calibration procedures us-
of Analysis for each batch of solvent from the supplier.
ing TMC reference oils, including their storage and conditions
7.3 Contact Pattern Marking Compound—Wayne Metal of use, and the conduct and reporting of reference oil test
Working Compound # M 99B 111A or equivalent.
results.
7.4 Test Oil—Use 3.5 pt (1655 mL) of test lubricant. 9.2 Annex A3 describes TMC maintenance activities in-
cluding special reference oil tests, special use of the reference
8. Preparation of Apparatus
oil calibration system, donated reference oil test programs,
8.1 Cleaning of Reusable Hardware—Clean as necessary
introduction of new reference oils, and issuance of TMC
with cleaning solvent (see 7.2) all reusable parts including:
information letters and memoranda.
axle shafts, thermocouples, axle housing cover, and all associ-
9.3 Annex A4 provides information regarding how new
ated drain pans and funnels used for the addition of and
laboratories can become part of the TMC Monitoring System,
collection of test oil.
and the role of the TMC in determining precision of monitored
8.2 Preparation of Axle:
test methods.
8.2.1 Pretest contact pattern procedure (see Annex A9).
9.4 Test Stand Calibration—Calibration is established upon
8.2.2 Record break and turn.
satisfactory completion of a reference oil test sequence that
8.2.3 Record the backlash reported from the manufacturer.
meets established reference oil targets.
The readings shall be between 0.004 in. and 0.012 in.
9.4.1 Each calibration sequence consists of three operation-
(0.102 mm to 0.305 mm).
ally valid and statistically acceptable reference oil tests.
8.2.3.1 Measure and record backlash at four equally spaced
9.4.2 When a calibration is being performed after the
locations. Report the average and the four readings.
twentieth non-reference oil test on a previously calibrated test
8.2.4 Proceed to 8.2.9 if contact pattern and backlash are
stand, or after three months since the last satisfactory reference
acceptable. Proceed to 8.2.5 if the contact pattern or backlash
oil test, perform a single operationally valid and statistically
needs adjustment.
acceptable reference oil test.
8.2.5 Follow Dana Model 44 Maintenance Manual if
9.4.2.1 The calibration sequence consists of the new test and
contact pattern or backlash needs to be adjusted.
the last two calibration tests performed.
8.2.6 Assemble the gear unit using Dana Model 44 Main-
9.4.3 Each operationally valid test is considered statistically
tenance Manual. Apply gear contact pattern grease on the
acceptable if the end of test pinion coast side scoring meets the
drive and coast side of the ring. Place a 30 lbf-ft 6 5 lbf-ft
Shewhart limits as published by the Test Monitoring Center.
(40.7 N·m 6 6.8 N·m) turning torque on the ring and pinion.
Specific Shewhart limits are defined for each gear batch and
Rotate ring and pinion through the gear contact pattern grease
reference oil combination.
on the drive and coast side.
9.4.3.1 Repeat any operationally valid calibration test in the
8.2.7 Proceed to 8.2.8 if the contact pattern and backlash are
calibration sequence with an end-of-test pinion coast side
acceptable. If the contact pattern requires further adjustment,
scoring value exceeding the Shewhart limits until acceptable
repeat 8.2.5 and 8.2.6 until an acceptable pattern is obtained.
pinion scoring results are achieved.
8.2.8 Measure and record backlash at four equally spaced
9.5 New Test Stand Calibration—A new test stand is con-
locations. Report the average and the four readings.
sidered calibrated upon completion of satisfactory reference oil
8.2.9 Clean the gear with cleaning solvent (see 7.2) when
tests (assigned by the TMC) that meet established reference oil
gear contact pattern and backlash are at acceptable levels.
targets.
8.2.10 Cleaning—Wash the test unit in cleaning solvent (see
9.5.1 New test stand inspection by the TMC is also required
7.2), paying particular attention to the pinion bearing to remove
to complete the calibration.
all preservative oil. Blow dry with clean dry compressed air.
8.2.11 Install axle shafts in test unit.
9.6 In-Service Stand Calibration—Calibrate previously ref-
8.2.12 Lubricate the carrier bearing, pinion bearings, differ-
erenced test stands according to instructions provided in 9.4;
ential gears, and the ring and pinion gears using 3.5 pt 6 0.1 pt
that is, after every twentieth non-reference oil test, or after
(1655 mL 6 50 mL) of test lubricant.
three months since the last acceptable reference oil test
8.2.13 Install the axle cover plate with gasket. It is not
sequence.
permissible to drain the oil and recharge the test axle once the
9.6.1 Also, if any of the special circumstances described
test oil has been charged to the axle.
below are involved, calibrate with a new four reference oil test
calibration sequence including a new discrimination oil run:
The gear marking compound is made by Wayne Metal Working Company. 9.6.1.1 After a test stand is moved, or
D7452 − 24
9.6.1.2 After changing axle batches, or 9.10 Assign a sequential test run number to every test start
on any test stand before testing begins. All tests, including
9.6.1.3 After changing throttle settings, or
aborted starts and operationally invalid tests, shall retain their
9.6.1.4 After changing torque settings, or
test number.
9.6.1.5 After major computer changes, or
9.11 Instrument Calibration—Calibrate the wheel and pin-
9.6.1.6 After a test not conforming to this test method was
ion speed measuring systems and axle oil temperature control
run in the stand since the last acceptable reference test, or
system at least every six months or 60 non-reference oil tests,
9.6.1.7 After 6 months since the last valid L42 calibration
whichever occurs first. Perform an instrument calibration
test, or
against a known standard traceable to either the National
9.6.1.8 After two reference oil calibration attempts are made
Institute of Standards and Technology (NIST) or to a physical
resulting in the end-of-test pinion coast side scoring not
constant.
meeting the Shewhart limits as published by the Test Monitor-
9.11.1 Prior to each reference oil test sequence, calibrate the
ing Center, or the tests are statistically unacceptable or opera-
pinion torque measuring device using a dead weight calibra-
tionally invalid.
tion. Perform the calibration on both the positive (drive) and
9.6.2 If a new three reference oil test calibration sequence is
negative (coast) side of zero.
being attempted, there shall not be more than five attempts
9.11.2 Engine Throttle Body Calibration—Calibrate prior to
between the first and last run numbers.
every calibration sequence.
9.6.2.1 If the discrimination oil test (see 9.7) is also
9.11.2.1 Warm the engine up until the coolant temperature is
required, there shall not be more than eight attempts between
greater than 150 °F (65.6 °C).
the first and last run numbers.
9.11.2.2 Connect a voltmeter to the throttle position sensor
(TPS) to measure the TPS voltage sent to the engine ECM.
9.7 Discrimination Oil Testing—Conduct a discrimination
9.11.2.3 Adjust the Foxboro/Jordon zero potentiometer to
oil test on the test stand every six months from the completion
close the throttle until engine idle speed is at 675 r ⁄min 6
of the last test in the calibration sequence or after four
75 r ⁄min. Record the TPS voltage.
calibration sequences.
9.11.2.4 Set the throttle controller at 100 % output. Adjust
9.7.1 Discrimination Oils approved by the L-42 Surveil-
the Foxboro/Jordon “span” potentiometer until the observed
lance Panel are oils that demonstrate lower-performance levels
TPS voltage is 1.3 V 6 0.1 V higher than the voltage recorded
compared to that of regular TMC reference oils.
in 9.11.2.3.
9.7.2 The end-of-test pinion coast side scoring value of the
discrimination oil test shall be a minimum of twice the average
10. Procedure for Conducting the Test
value of the three acceptable reference oil tests for the
10.1 The test axles are batch specific. See TMC Memo
discrimination test to be considered acceptable. The discrimi-
94-200 for approved gear batches and test targets.
nation oil test may be conducted at any time during the
calibration sequence. If the discrimination oil test isconducted
10.2 Gear Conditioning—All ramp targets should be
at the end of the calibration sequence and a second discrimi-
reached in approximately five min. Minimize drive torque to
nation oil test is needed, this second discrimination oil test, if
prevent drive side scoring.
acceptable, will count as 1 of the 20 non-reference oil tests.
10.2.1 Conditioning 1:
Repeat the complete calibration sequence (the three reference
10.2.1.1 Set the axle oil temperature control equipment at a
oil tests and the discrimination oil test) if both discrimination
set point of 225 °F (107.2 °C). When the axle oil temperature
oil tests do not meet the above requirements.
reaches set point, maintain the temperature within 225 °F 6
10 °F (107.2 °C 6 5.6 °C) until conditioning is complete.
9.8 Correction Factor—When using TMC Reference Oil
10.2.1.2 Shift Gears—With the engine at operating tempera-
117 for stand calibration, add 6 % to the pinion scoring result
ture set the engine idle speed to 700 r ⁄min 6 200 r ⁄min
and add 4 % to the ring scoring result. Report both the rated
(73 rad ⁄s 6 21 rad ⁄s). Prior to shifting gears set the engine
scoring and the corrected scoring in the space provided in the
speed manual output to achieve approximately 2000 r ⁄min
test report.
(209 rad ⁄s). With no torque on the dynamometers smoothly
9.9 Reference Test Frequency—The test stand calibration
shift the transmission through the gears (without bucking the
period is defined as three months or 20 tests, whichever occurs
axle) allowing the engine to recover to approximately
first. It begins on the completion date of an operationally and
1500 r ⁄min (157 rad ⁄s) between shifts. Shift through the gears
statistically acceptable reference oil test series as determined
until 1:1 ratio (4th gear) is reached.
by the TMC. Any test started on or before the stand calibration
10.2.1.3 Ramp & Condition—Set data acquisition to record
expiration date is defined to have been run on a calibrated
pinion torque, wheel speed and axle temperature at a minimum
stand.
of 1 Hz. Accelerate both wheels to a speed of 575 r ⁄min 6
9.9.1 When a test stand is out of calibration for a period of
5 r ⁄min (60 rad ⁄s 6 0.5 rad ⁄s) (pinion speed 2352 r ⁄min 6
six months or longer, renumber the stand, and follow LTMS
20 r ⁄min (246 rad ⁄s 6 2 rad ⁄s)). Apply a dynamometer exci-
guidelines for new stand introduction.
tation to achieve a pinion torque of 60 lbf-ft 6 20 lbf-ft
9.9.2 Report modification of test stand apparatus or comple- (81 N·m 6 27 N·m). When both conditions are met, begin
tion of any nonstandard test on a calibrated test stand to the conditioning phase 1 and maintain for 10 min 6 0.5 min. At
TMC immediately. the end of this steady state operation lock dynamometer
D7452 − 24
excitation at the output necessary to achieve 60 lbf-ft (81 N·m). between shifts. Shift through the gears until 1:1 ratio (4th gear)
Immediately proceed to 10.2.2. is reached. Set temperature control set point to 200 ºF
(93.3 °C).
10.2.2 Conditioning 2—Set data acquisition to record pinion
10.3.1.2 Set data acquisition to record pinion torque, wheel
torque and wheel speed at a minimum of 10 Hz and axle
speed and axle temperature at a minimum of 1 Hz. Slowly
temperature at a minimum of 1 Hz. While maintaining the
accelerate the driveline until wheel speed is 530 r ⁄min 6
fixed dynamometer excitation, slowly cycle the wheel speed
5 r ⁄min (55 rad ⁄s 6 0.5 rad ⁄s) (pinion speed 2168 r ⁄min 6
from 575 r ⁄min 6 20 r ⁄min (60 rad ⁄s 6 0.5 rad ⁄s) to 385 r ⁄min
20 r ⁄min (227 rad ⁄s 6 2 rad ⁄s)). Apply dynamometers excita-
6 20 r ⁄min (40 rad ⁄s 6 0.5 rad/s). Maintain the fixed dyna-
tion to maintain 50 lbf-ft 6 10 lbf-ft (68 N·m 6 14 N·m)
mometer excitation settings and control throttle movement
pinion torque.
slowly enough to maintain pinion torque values sufficient to
10.3.1.3 Differential housing oil temperature shall be 200 °F
properly condition the drive and coast side of the axle.
6 5 °F (93.3 °C 6 2.8 °C) at the start of Shock Series 1. See
Complete four cycles then immediately proceed to 10.2.3. The
A5.2.2.2 for L-42 Canadian Version test.
total time of the four cycles shall not exceed 5 min.
10.3.1.4 Once pinion speed, pinion torque, and axle lubri-
NOTE 1—It is believed that if the shape of both drive and coast
cant temperature reach steady state, lock dynamometer excita-
segments of Conditioning 2 and Conditioning 4 are flat topped in nature
tion at the output necessary to maintain 50 lbf-ft 6 10 lbf-ft
(without any spikes in the acceleration or deceleration torque that would
(68 N·m 6 14 N·m), turn off axle oil temperature control, and
indicate a shock) the torque values found from this data stream will be a
better representation of the gear conditioning.
proceed immediately to 10.3.2.
10.3.2 Shock Series 1 Procedure:
10.2.3 Conditioning 3:
10.3.2.1 Turn the axle cooling water off after the ramp-up of
10.2.3.1 Maintain the axle oil temperature control at 225 °F
Shock Series 1. Ensure that the axle cooling water is off during
6 10 °F (107.2 °C 6 5.6 °C).
the shocks. See A5.2.2.3 for L-42 Canadian Version test.
10.2.3.2 Ramp & Condition—Set data acquisition to record
10.3.2.2 Record axle oil temperature at the start of Shock
pinion torque, pinion speed and axle temperature at a minimum
Series 1 on the appropriate form. Maintain the fixed dynamom-
of 1 Hz. Accelerate both wheels to a wheel r/min speed of
eter excitation until the transmission is shifted into neutral at
815 r ⁄min 6 5 r ⁄min (85 rad ⁄s 6 0.5 rad ⁄s). Apply a dyna-
end of Shock Series 1 in 10.3.2.3.
mometer excitation to achieve a pinion torque of 70 lbf-ft 6
10.3.2.3 Set data acquisition to acquire pinion torque data at
20 lbf-ft (95 N·m 6 27 N·m). When both conditions are met,
a minimum of 100 Hz, wheel speed at a minimum of 10 Hz and
maintain for 20 min 6 0.5 min. At the end of this steady state
axle temperature at a minimum of 1 Hz While maintaining the
operation lock dynamometer excitation at the output necessary
fixed dynamometer excitation begin cycling the wheel speed
to achieve 70 lbf-ft (95 N·m). Immediately proceed to 10.2.4.
from 530 r ⁄min 6 20 r ⁄min (55 rad ⁄s 6 2 rad ⁄s) to 1050 r ⁄min
10.2.4 Conditioning 4:
6 20 r ⁄min (110 rad ⁄s 6 2 rad ⁄s). Complete five cycles,
10.2.4.1 Set data acquisition to record pinion torque and
ending by accelerating the engine to bring the pinion torque
wheel speed at a minimum of 10 Hz and axle temperature at a
back to near 0, then proceed to 10.3.2.4.
minimum of 1 Hz. While maintaining the fixed dynamometer
10.3.2.4 Shift transmission into neutral to avoid additional
excitation, slowly cycle the wheel speed from 815 r ⁄min 6
coast side conditioning. Bring engine speed down to idle.
20 r ⁄min (85 rad ⁄s 6 2 rad ⁄s) to 670 r ⁄min 6 20 r ⁄min
10.4 Inspection 2—(Warning—Differential is extremely
(70 rad ⁄s 6 2 rad ⁄s). Maintain the fixed dynamometer excita-
hot. Hot oil can produce vapors.)
tion settings and control throttle movement slowly enough to
10.4.1 Inspect ring gear and report approximate drive and
maintain pinion torque values sufficient to properly condition
coast percent scoring. Inspection should take approximately
the drive and coast side of the axle. Complete four cycles then
5 min. Make every effort to minimize the time spent during the
immediately proceed to 10.2.4.2. The total time of the four
inspection to maintain the axle temperature. Do not cool the
cycles shall not exceed 5 min.
axle at the end of Shock Series 1. Ensure the cooling water
10.2.4.2 Shift transmission into neutral to avoid additional
remains turned off for the remainder of the test. Table A5.1
coast side conditioning. Bring engine r/min down to idle.
shows alternative test versions.
10.2.5 Inspection 1—(Warning—Differential is extremely
10.5 Shock Series 2:
hot. Hot oil can produce vapors.)
10.5.1 Shock Series 2 Preparation:
10.2.5.1 Inspect ring gear and report approximate drive and
10.5.1.1 If the axle oil temperature is greater than 280 ºF
coast percent scoring. Inspection should take approximately
(137.8 ºC) after Inspection 2, allow the axle oil temperature to
5 min. Make an effort to minimize the time spent during the
cool (without cooling water) until axle oil temperature is less
inspection.
than or equal to 280 ºF (137.8 ºC) before shifting transmission
10.3 Shock Series 1:
through the gears. If the axle oil temperature is less than or
10.3.1 Shock Series 1 Preparation:
equal to 280 ºF (137.8 ºC) after Inspection 2, proceed imme-
10.3.1.1 Set the engine speed manual output to achieve diately to 10.5.1.2.
approximately 2000 r ⁄min (209 rad ⁄s). prior to shifting gears. 10.5.1.2 Set the engine speed manual output to achieve
With no load on the dynamometers smoothly shift the trans- approximately 2000 r ⁄min (209 rad ⁄s). prior to shifting gears.
mission through the gears (without bucking the axle) allowing With no torque on the dynamometers smoothly shift the
the engine to recover to approximately 1500 rpm (157 rad ⁄s) transmission through the gears (without bucking the axle)
D7452 − 24
allowing the engine to recover to approximately 1500 rpm 11.3 Reference oil tests, other than a discrimination oil test,
(157 rad ⁄s) between shifts. Shift through the gears until 1:1.67 and non-reference oil tests that exhibit end of test ring coast
ratio (3rd gear) is reached. side scoring greater than end of test pinion coast side scoring
are non-interpretable.
10.5.1.3 Set data acquisition to record pinion torque, wheel
speed and axle temperature at a minimum of 1 Hz. Slowly
11.4 Consider reference oil tests, other than the discrimina-
accelerate the driveline until wheel speed is 530 r ⁄min 6
tion oil tests, and non-reference oil tests that exhibit drive side
5 r ⁄min (55 rad ⁄s 6 0.5 rad ⁄s) (pinion speed 2168 r ⁄min 6
scoring non-interpretable.
20 r ⁄min (227 rad ⁄s 6 2 rad ⁄s)). Apply dynamometers excita-
11.5 Test Validity—The test is determined to be operation-
tion to achieve 70 lbf-ft 6 10 lbf-ft (95 N·m 6 14 N·m) pinion
ally valid if the percent deviation of the critical operating
torque. When steady state operation is achieved lock dyna-
parameters and number of shutdowns are within the limits
mometer excitation at the output necessary to maintain
specified and defined in Annex A8.
70 lbf-ft 6 10 lbf-ft (95 N·m 6 14 N·m).
11.6 Round test results according to Practice E29.
10.5.1.4 Record axle oil temperature at the start of Shock
Series 2 on the appropriate form. Axle oil temperature shall be
12. Interpretation of Operational Data
less than or equal to 280 ºF (137.8 ºC) at the start of Shock
12.1 Data Stream Interpretation—Figs. A6.11-A6.21 are
Series 2. See A5.2.2.4 for L-42 Canadian Version test.
required in the final test report. Examples shown are meant to
10.5.1.5 Set data acquisition to acquire pinion torque data at
display all data collected and optimize the resolution of the
a minimum of 100 Hz, wheel speed at a minimum of 10 Hz and
data. The X and Y axis may be rescaled to achieve this.
axle temperature at a minimum of 1 Hz While maintaining the
12.1.1 Lubricant Temperature:
fixed dynamometer excitation begin cycling the wheel speed
12.1.1.1 The initial oil temperature for each test sequence
from 530 r ⁄min 6 20 r ⁄min (55 rad ⁄s 6 2 rad ⁄s) to 630 r ⁄min
shall consist of the average of the first 5 s of data during the
6 20 r ⁄min (66 rad ⁄s 6 2 rad ⁄s). Complete ten cycles, ending
sequence.
by accelerating the engine to bring the pinion torque back to
12.1.1.2 The maximum oil temperature for each test se-
near 0, then proceed to 10.5.1.6.
quence is the single maximum value experienced during the
10.5.1.6 Shift transmission into neutral to avoid additional sequence.
12.1.1.3 Referring to Fig. A6.21, plot all data collected from
coast side conditioning. Bring engine speed down to idle.
the start of Conditioning 1 to the end of Shock Series 2. Use the
10.5.1.7 Record end of test time and test minutes in the
X axis as the elapse time data.
appropriate test fields.
12.1.2 Wheel Speeds:
10.6 Tear Down Procedure—(Warning—The axle is very
12.1.2.1 During Conditioning 1, see Fig. A6.11 location (A)
hot. Use caution.)
and Conditioning 3, see Fig. A6.12 location (D), the reported
10.6.1 Disconnect dynamometers and drive shafts. Perform
wheel speeds shall be the average over the steady-state
end of test procedures. sequence.
12.1.2.2 Referring to Figs. A6.11 and A6.12, during Condi-
10.6.2 Check backlash in four equally spaced locations and
tioning 2 or 4, the value of the maximum and minimum single
record measurements on the appropriate form.
scan conditioning 2 and 4 wheel speeds are located at (B -B
1 3
10.6.3 Disassemble axle for rating of ring and pinion.
and C -C ) and (E -E and F -F ) respectively. For both
1 4 1 3 1 4
10.6.4 Clean ring and pinion with cleaning solvent (see 7.2)
conditioning 2 and 4, independently report the maximum,
and dry.
minimum, and average of the single scan maximum speeds and
the maximum, minimum, and average of the single scan
11. Determination of Test Results
minimum speeds by including all peaks and valleys not
connected to a steady state operating condition phase.
11.1 Part Rating:
12.1.2.3 Referring to Fig. A6.13, during Shock Series 1, the
11.1.1 Rate and report both drive and coast side of pinion
value of the maximum and minimum single scan Shock Series
and ring gear for percent of total tooth area that exhibits
1 wheel speeds are to be found at locations (G -G ) and
1 5
scoring, see ASTM Distress Rating Manual 21 (formerly CRC
(H -H ) respectively. Report the maximum, minimum, and
1 4
Manual 21). Compare the percent scoring for the non-reference
average of the single scan maximum speeds and the maximum,
oil tests to the percent scoring for the three most recent
minimum, and average of the single scan minimum speeds by
acceptable reference oil tests.
including all peaks and valleys not connected to a steady state
11.1.2 For a valid rating ensure that the individual rating the
operating condition phase.
test has participated in an ASTM gear rater calibration work-
12.1.2.4 Referring to Fig. A6.14, during Shock Series 2, the
shop within the previous twelve months.
value of the maximum and minimum single scan Shock Series
11.2 A non-reference oil test that has not been run in a 2 wheel speeds are to be found at locations (I -I ) and (J -J )
1 10 1 9
calibrated test stand or not conducted on approved hardware or respectively. Report the maximum, minimum, and average of
both is considered non-interpretable. Note on the cover page of the single scan maximum speeds and the maximum, minimum,
the test report that the test is non-interpretable and that it has and average of the single scan minimum speeds by including
not been conducted in a valid manner in accordance with the all peaks and valleys not connected to a steady state operating
test method. condition phase.
D7452 − 24
12.1.3 Pinion Torque Conditioning 1–4: average of the single scan maximum pinion torques and the
maximum, minimum, and average of the single scan minimum
12.1.3.1 During Conditioning 1, see Fig. A6.15 location (K)
pinion torques.
and Conditioning 3, see Fig. A6.16 location (N), the reported
12.1.5.3 Calculate and report the maximum, minimum, and
pinion torque is the average torque over the steady state
average drive side gear contact segment time. Calculate and
sequence.
report the maximum, minimum, and average coast side gear
12.1.3.2 Refer to Fig. A6.17, Conditioning 2 pinion torque,
contact segment time. For these time calculations, ignore the
and Fig. A6.18, Conditioning 4 pinion torque. Locations
first drive side segment and the last coast side segment since
(L -L ) and locations (M -M ) represent the zero line crossings
0 7 0 7
zero crossings are not well defined.
for the pinion torque. The drive side gear contact segments are
12.1.6 Total Test Time:
between points 1 and 2, 3 and 4, and 5 and 6, and 7 and beyond.
12.1.6.1 Calculate and report total test time starting from the
The coast side gear contact segments are between points 0 and
beginning of Conditioning 1 to the end of Shock 2.
1, 2 and 3, 4 and 5 and 6 and 7.
12.1.3.3 Referring to Figs. A6.17 and A6.18, Conditioning 2
13. Report
pinion torque and conditioning 4 pinion torque, the maximum
13.1 For reference oil results, use the standardized report
and minimum single scan conditioning 2 and 4 pinion torque
form set available from the ASTM TMC.
values are located at (B -B and C -C ) and (E -E and F -F )
1 3 1 4 1 3 1 4
NOTE 2—Report the non-reference oil test results on these same forms
respectively. For both conditioning 2 and 4, independently
if the results are intended to be submitted as candidate oil results against
report the maximum, minimum, and average of the single scan
a specification.
maximum pinion torques and the maximum, minimum, and
13.1.1 Fill out the report forms according to the formats
average of the single scan minimum pinion torques by includ-
shown in the data dictionary.
ing all peaks and valleys not connected to a steady state
13.1.2 Transmit results to the TMC within 5 working days
operating condition phase. Ignore the drive side gear contact
of test completion.
segments beyond zero crossings 7 since their stop times are not
13.1.3 Transmit the results electronically as described in the
well defined.
ASTM Data Communications Committee Test Report Trans-
12.1.4 Pinion Torque—Shock Series 1:
mission Model (Section 2 — Flat File Transmission Format)
12.1.4.1 Referring to Fig. A6.19, the zero pinion torque
available from the ASTM TMC. Upload files via the TMC’s
crossings (O -O ) are located where the pinion torque value
0 9
website.
crosses zero. The coast side gear contact segments are between
13.2 Report all reference oil test results, whether aborted,
points 0 and 1, 2 and 3, 4 and 5, 6 and 7, and 8 and 9. The drive
invalidated, or successfully completed, to the TMC.
side gear contact segments are between points 0 and prior, 1
and 2, 3 and 4, 5 and 6, and 7 and 8.
13.3 Deviations from Test Operational Limits—Report all
12.1.4.2 Referring to Fig. A6.19, during Shock Series 1, the
deviations from specified test operational limits.
value of the maximum and minimum single scan Shock Series
13.4 Precision of Reported Units—Use the Practice E29
1 pinion torques is to be found at locations (P -P ) and (Q -Q )
1 5 1 5
rounding off method for critical pass/fail test result data.
respectively. Report the maximum, minimum, and average of
Report the data to the same precision as indicated in data
the single scan maximum pinion torques and the maximum,
dictionary.
minimum, and average of the single scan minimum pinion
13.5 In the space provided, note the time, date, test hour,
torques.
and duration of any shutdown or off-test condition. Document
12.1.4.3 Calculate and report the maximum, minimum, and
the outcome of all prior reference oil tests from the current
average drive side gear contact segment time. Calculate and
calibration sequence that were operationally or statistically
report the maximum, minimum, and average coast side gear
invalid.
contact segment time. For these time calculations, ignore the
13.6 If a calibration period is extended beyond the normal
first drive side segment and the last coast side segment since
calibration period length, make a note in the comment section
zero crossings are not well defined.
and attach a written confirmation of the granted extension from
12.1.5 Pinion Torque—Shock Series 2:
the TMC to the test report. List the outcomes of previous runs
12.1.5.1 Referring to Fig. A6.20, the zero pinion torque
that may need to be considered as part of the extension in the
...

This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: D7452 − 22 D7452 − 24
Standard Test Method for
Evaluation of the Load Carrying Properties of Lubricants
Used for Final Drive Axles, Under Conditions of High Speed
and Shock Loading
This standard is issued under the fixed designation D7452; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
INTRODUCTION
Portions of this test method are written for use by laboratories that make use of ASTM Test
Monitoring Center (TMC) services (see Annex A1 – Annex A4).
The TMC provides reference oils, and engineering and statistical services to laboratories that desire
to produce test results that are statistically similar to those produced by laboratories previously
calibrated by the TMC.
In general, the Test Purchaser decides if a calibrated test stand is to be used. Organizations such as
the American Chemistry Council require that a laboratory use the TMC services as part of their test
registration process. In addition, the American Petroleum Institute and the Gear Lubricant Review
Committee of the Lubricant Review Institute (SAE International) require that a laboratory use the
TMC services in seeking qualification of oils against their specifications.
The advantage of using the TMC services to calibrate test stands is that the test laboratory (and
hence the Test Purchaser) has an assurance that the test stand was operating at the proper level of test
severity. It should also be borne in mind that results obtained in a non-calibrated test stand may not
be the same as those obtained in a test stand participating in the ASTM TMC services process.
Laboratories that choose not to use the TMC services may simply disregard these portions.
1. Scope*
1.1 This test method covers the determination of the anti-scoring properties of final drive axle lubricating oils when subjected to
high-speed and shock conditions. This test method is commonly referred to as the L-42 test.
1.2 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical
conversions to SI units that are provided for information only and are not considered standard.
1.2.1 Exceptions—SI units are provided for all parameters except where there is no direct equivalent such as the units for screw
threads, National Pipe Threads/diameters, tubing size, and single source equipment suppliers.
This test method is under the jurisdiction of ASTM Committee D02 on Petroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility of Subcommittee
D02.B0.03 on Automotive Gear Lubricants & Fluids.
Current edition approved Nov. 1, 2022March 1, 2024. Published November 2022March 2024. Originally approved in 2008. Last previous edition approved in 20192022
ɛ1
as D7452 – 19D7452 – 22. . DOI: 10.1520/D7452-22.10.1520/D7452-24.
Until the next revision of this test method, the ASTM Test Monitoring Center (TMC) will update changes in this test method by means of information letters. Information
letters may be obtained from the ASTM Test Monitoring Center, 203 Armstrong Drive, Freeport, PA 16229, Attention: Director. This edition incorporates revisions in all
information Letters through No. 22-1.23-1. The TMC is also a source of reference oils.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D7452 − 24
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility
of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of
regulatory limitations prior to use. Specific warning information is given in Sections 4 and 7.
1.4 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
2. Referenced Documents
2.1 ASTM Standards:
D235 Specification for Mineral Spirits (Petroleum Spirits) (Hydrocarbon Dry Cleaning Solvent)
E29 Practice for Using Significant Digits in Test Data to Determine Conformance with Specifications
2.2 Society of Automotive Engineers Standards:
SAE J308 Information Report on Axle and Manual Transmission Lubricants
SAE J2360 Lubricating Oil, Gear Multipurpose (Metric) Military Use
3. Terminology
3.1 Definitions of Terms Specific to This Standard:
3.1.1 coast side, n—the convex side of the pinion and the concave side of the ring gear which are in contact during deceleration
in a forward gear.
ASTM Distress Rating Manual 21
3.1.2 drive side, n—the concave side of the pinion and the convex side of the ring gear which are in contact during acceleration
in a forward gear.
ASTM Distress Rating Manual 21
3.1.3 scoring, n—on the ring and the pinion gear teeth, the displacement of metal by local momentary welding from the gear tooth,
resulting in the development of a matt, or frosted dull surface.
ASTM Distress Rating Manual 21
4. Summary of Test Method
4.1 Charge a specially prepared light duty hypoid rear axle (Dana Model 44 ASTM Part No. 044AA100-1) with the lubricant
sample to be tested (see 10.1). Mount the axle between two load absorbing dynamometers which are driven with a V-8 gasoline
engine through a manual transmission.
4.2 Condition the test axle with light loads at different speed, torque and temperature conditions on both the drive and coast sides
of the gears. (Warning—High-speed rotating equipment, electrical shock, high-temperature surfaces.) After conditioning, subject
the test axle to high speed and shock loadings at higher temperatures.
4.3 Rate the drive and coast side of the pinion and ring gears at the end of test (EOT) for scoring distress.
5. Significance and Use
5.1 Final drive axles are often subjected to severe service where they encounter high speed shock torque conditions, characterized
by sudden accelerations and decelerations. This severe service can lead to scoring distress on the ring gear and pinion surface. This
test method measures anti-scoring properties of final drive lubricants.
5.2 This test method is used or referred to in the following documents:
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
Available from Society of Automotive Engineers (SAE), 400 Commonwealth Dr., Warrendale, PA 15096-0001, http://www.sae.org.
Formerly known as CRC Rating Manual, No. 21. Available from the ASTM website, www.astm.org, ASTM Stock No. TMCMNL21.
Parts and Model 44 Maintenance Manual available from Dana Corporation, P.O. Box 2424, Fort Wayne, IN 46801.
D7452 − 24
5.2.1 American Petroleum Institute (API) Publication 1560.
5.2.2 SAE J308 and SAE J2360.
6. Apparatus
6.1 This test method provides a description of essential apparatus features, including mandatory equipment type and performance
specifications where established.
6.2 Test Axle—The test unit consists of a Dana model 44 rear axle, 45 to 11 (4.09) ratio, and uncoated gears. (Dana ASTM part
number 044AA100-1. See 10.1.)
6.3 Cover Plate—Modify the rear cover plate of the test unit to provide an inspection port and thermocouple fitting. Locate the
thermocouple fitting by using the locating fixture shown in Fig. A6.1. An optional ⁄4 in. NPT (National Pipe Thread) drain fitting
may be added.
6.4 Axle Shaft Assemble—Use a Ford Axle shaft assembly, (Dana Part No. 26762-14X ) or equivalent with this test method.
6.5 Hinge Plate Stand Assembly—Mount and secure the test unit in place on the hinge plate assembly, see Figs. A6.6-A6.9.
6.6 Temperature Control System—The temperature control apparatus consists of a thermocouple, a temperature recording system,
temperature controller and a cooling system that is able to maintain lubricant temperature at specified conditions.
6.6.1 Thermocouple—Install the thermocouple such that the thermocouple tip is flush with the cover plate lip by placing the cover
plate face on a flat surface and inserting the thermocouple into the cover plate until the thermocouple tip is flush with the flat
surface. For recording and control of the test lubricant temperature, use a ⁄8 in. (3.2 mm) diameter J or K type closed tip style
thermocouple.
6.6.2 Temperature Recording System—Throughout the test, ensure the temperature recording system records the temperature of
the test oil at a minimum frequency of 1 Hz.
6.6.3 Temperature Controller—Proportional-Integral-Derivative (PID) type; percent output adjustable.
6.6.4 Axle Cooling—Use three spray nozzles to distribute water over the cover plate and axle housing as shown in Fig. A6.2.
Actuate the water control valve by the temperature PID control system.
6.6.4.1 Depending on how the system is plumbed, use spray nozzles in any combination of the following part numbers: Straight
Male NPT (Part No. 3/8GG-SS22), 90° Male NPT (Part No. 3/8GGA-SS22), Straight Female NPT (Part No. 3/8G-SS22), and 90°
8,9
Female NPT (Part No. 3/8GA-SS22).
6.6.4.2 Use a single control valve to control the cooling water supply. The control shall be a ⁄2 in. (12.7 mm) two-way, C linear
trim, air to close, Research Control valve. Use a single PID loop to maintain the axle lubricant temperature control for both the
Standard and Canadian version test. A separate PID loop control for each version is not permitted. See Annex A5.
3 1
6.6.4.3 Use only ⁄8 in. or ⁄2 in. (9.5 mm or 12.7 mm) line material to the spray nozzles.
6.6.4.4 Use a minimum supply water pressure of 25 psig (172 kPa) to the control valve.
6.6.4.5 Use an axle containment box as shown in Fig. A6.10. The purpose is to contain water.
API Publication 1560, Lubricant Service Designations for Automotive Manual Transmissions, Manual Transaxles, and Axles, American Petroleum Institute, Washington,
DC.
The sole source supply of the apparatus known to the committee at this time is Spray Systems Company, and can be purchased through E. I. Pfaff Company, 3443 Edwards
Road, Suite D, Cincinnati, OH 45208.
If you are aware of alternative suppliers, please provide this information to ASTM International Headquarters. Your comments will receive careful consideration at a
meeting of the responsible technical committee, which you may attend.
D7452 − 24
6.6.4.6 Use a locating pin or stop block as an indexing device to ensure that all subsequent axle installations are consistently
installed perpendicular with the axle housing cover to engine and transmission drive-shaft centerline.
6.7 Torque Meter—Include in the test equipment a torque meter installed in the drive shaft (see Figs. A6.3-A6.5) to measure the
torque applied to the pinion. Install a Himmelstein inline torque meter Model numbers MCRT28061T(1-4) or MCRT2661TN(1-
9,10
4) without a foot mount and a range of 10 000 lb-in. (1130 N·m) shall be installed to measure pinion torque. Additional suffix
letters only indicate allowable options.
6.8 Signal Conditioning—Use a Himmelstein Models 701 or 711 strain gage conditioner for signal conditioning. Set the low pass
cut-off frequency at 10 Hz.
6.9 Digital Data Acquisition System—System requires capability of measuring a minimum of five channels at sampling
frequencies outlined in Section 10.
6.9.1 Do not use hardware or software filtering for the pinion torque channel during data acquisition periods of the test.
9,11
6.10 Dynamometers—Two axle dynamometers (Midwest Dynamatic, Model 3232) with suitable control equipment capable of
maintaining specified test conditions.
6.11 Engine Speed Control—System requires a device to maintain steady state conditions and also provide adjustable throttle
acceleration and deceleration rates to attain specified shock loading torques.
9,12
6.11.1 Throttle Controller System—Use a Foxboro/Jordan Controller, Model AD7530. Use a power transformer from Acme
Electric Corp. PN T-1-81058 or equivalent, primary volts 120X240, secondary volts (120 V primary by 240 V secondary), 16/32
(13 mm) center tap, 0.500 kVA (0.5 kW) in conjunction with the Foxboro/Jordan Controller.
6.12 Connecting Shafts—Use connecting shafts of equal length 61 in. (25.4 mm) and less than 30 in. (762 mm) long from flange
face to flange face. Use a tubing diameter of 3.5 in. 6 0.2 in. (88.9 mm 6 5.1 mm) OD, with a wall thickness of 0.095 in. 6
0.005 in. (2.41 mm 6 0.13 mm) if tubing is required to fabricate the shafts. Ensure the shafts are dynamically (spin) balanced and
strong enough to handle torques up to 2100 lbf-ft (2847 N·m). Use an operating angle of 0° 6 0.5°.
TABLE 1 Recommended Power Train Replacement Parts List
Parts Part Number
Ramjet Engine Includes ECM 12495515
Five Speed Transmission 15747134 or
Bell Housing 15998496
Clutch Assembly 15002591
Throw Out Bearing 15705563
Dip Stick 10190942
Dip Stick Tube 12552920
Flywheel 10105832
Flywheel Bolt (6 req.) 12337973
Pilot Bearing 14061685
Master Cylinder 15727261
Actuating Cylinder 15046288
Pulley, Water Pump 14023155
Pulley, Crankshaft 14023147
Belt 9433720
Starter 10496873
Engine Control Unit 12489488
Throttle Body from 2000 Corvette. 17113669
Throttle Body TPS Connector P/N 12116247
Throttle Body Actuator Motor Connector P/N 12167121
K&N Inlet Air Filter P/N RD6020
The sole source supply of the apparatus known to the committee at this time is S. Himmelstein and Company, 2490 Pembroke Avenue, Hoffman Estates, IL 60195.
Available from Dyne Systems, P.O. Box 18 W209 N17391 Industrial Drive, Jackson, WI 53037.
Available from Fox/Jordan, Inc., 5607 West Douglas Avenue, Milwaukee, WI 53218.
D7452 − 24
6.13 Power Train—The power train consists of a gasoline powered V-8 GM performance Ramjet 5.7 L marine engine coupled
with a five speed manual transmission capable of supplying specified shock loading torques. The engine and transmission operating
angle shall be 0° 6 0.5°.
6.13.1 All recommended replacement parts are available through local General Motors dealers. A list of these replacement parts
are shown in Table 1. Do not make modifications to the engine that would affect the engines factory displacement or compression
ratio.
6.14 Drive Shaft—Welded steel tubing, 3.5 in. 6 0.2 in. (90 mm 6 5.1 mm) outside diameter, 0.095 in. 6 0.005 in. (2.41 mm 6
0.13 mm) wall thickness, 34.5 in. 6 1 in. (880 mm 6 25 mm) long from center weld to center weld. (See Figs. A6.3-A6.5.)
Dynamically (spin) balance the drive shaft and torque meter. The operating angle shall be 0° 6 0.5°.
13 14
6.14.1 Transmission U-Joint—(Spicer 5-178X) or Neapco 2-1435
6.14.2 Pinion U-Joint—(Spicer 5-153X).
6.14.3 Flange Yoke—Connects transmission yoke through u-joint to drive shaft.
6.14.4 Pinion Drive Shaft Slip Yoke—Connects the drive shaft through the u-joint to the axle yoke.
6.14.5 Flange Adaptor—Manufacture flange adapter to specifications in Figs. A6.4 and A6.5.
6.15 Spring Plate—Manufacture spring plates to specification as shown in Fig. A6.8.
6.16 Spring Plate Rod Connection—Mount a rod connecting the spring plate to the gear stand using ⁄2 in. (13 mm) spherical rod
ends. See Figs. A6.6 and A6.7.
7. Reagents and Materials
7.1 Sealing Compound—Where necessary, use Permatex No. 2 or equivalent.
7.2 Cleaning Solvent—Use solvent meeting ASTM D235 Type II, Class C requirements for Aromatic Content (0 to 2) % by
volume, Flash Point (142 °F ⁄61 °C, min) and Color (not darker than +25 on Saybolt Scale or 25 on Pt-Co Scale).
(Warning—Health hazard, combustible.) Obtain a Certificate of Analysis for each batch of solvent from the supplier.
7.3 Contact Pattern Marking Compound—Wayne Metal Working Compound # M 99B 111A or equivalent.
7.4 Test Oil—Use 3.5 pt (1655 mL) of test lubricant.
8. Preparation of Apparatus
8.1 Cleaning of Reusable Hardware—Clean as necessary with cleaning solvent (see 7.2) all reusable parts including: axle shafts,
thermocouples, axle housing cover, and all associated drain pans and funnels used for the addition of and collection of test oil.
8.2 Preparation of Axle:
8.2.1 Pretest contact pattern procedure (see Annex A9).
8.2.2 Record break and turn.
Available from any local drive shaft supplier.
Available from Neapco, LLC, 6735 Haggerty Rd., Belleville, MI 48111.
The gear marking compound is made by Wayne Metal Working Company.
D7452 − 24
8.2.3 Record the backlash reported from the manufacturer. The readings shall be between 0.004 in. and 0.012 in. (0.102 mm to
0.305 mm).
8.2.3.1 Measure and record backlash at four equally spaced locations. Report the average and the four readings.
8.2.4 Proceed to 8.2.9 if contact pattern and backlash are acceptable. Proceed to 8.2.5 if the contact pattern or backlash needs
adjustment.
8.2.5 Follow Dana Model 44 Maintenance Manual if contact pattern or backlash needs to be adjusted.
8.2.6 Assemble the gear unit using Dana Model 44 Maintenance Manual. Apply gear contact pattern grease on the drive and coast
side of the ring. Place a 30 lbf-ft 6 5 lbf-ft (40.7 N·m 6 6.8 N·m) turning torque on the ring and pinion. Rotate ring and pinion
through the gear contact pattern grease on the drive and coast side.
8.2.7 Proceed to 8.2.8 if the contact pattern and backlash are acceptable. If the contact pattern requires further adjustment, repeat
8.2.5 and 8.2.6 until an acceptable pattern is obtained.
8.2.8 Measure and record backlash at four equally spaced locations. Report the average and the four readings.
8.2.9 Clean the gear with cleaning solvent (see 7.2) when gear contact pattern and backlash are at acceptable levels.
8.2.10 Cleaning—Wash the test unit in cleaning solvent (see 7.2), paying particular attention to the pinion bearing to remove all
preservative oil. Blow dry with clean dry compressed air.
8.2.11 Install axle shafts in test unit.
8.2.12 Lubricate the carrier bearing, pinion bearings, differential gears, and the ring and pinion gears using 3.5 pt 6 0.1 pt
(1655 mL 6 50 mL) of test lubricant.
8.2.13 Install the axle cover plate with gasket. It is not permissible to drain the oil and recharge the test axle once the test oil has
been charged to the axle.
8.2.14 Install test unit on stand with pinion and axle shaft center lines horizontal. The operating angle shall be 0° 6 0.5°. After
installing the axle, ensure that the hinge plate assembly is free.
8.2.15 Connect the dynamometers and drive shaft to the test unit.
9. Calibration and Standardization
9.1 Annex A2 describes general calibration procedures using TMC reference oils, including their storage and conditions of use,
and the conduct and reporting of reference oil test results.
9.2 Annex A3 describes TMC maintenance activities including special reference oil tests, special use of the reference oil
calibration system, donated reference oil test programs, introduction of new reference oils, and issuance of TMC information letters
and memoranda.
9.3 Annex A4 provides information regarding how new laboratories can become part of the TMC Monitoring System, and the role
of the TMC in determining precision of monitored test methods.
9.4 Test Stand Calibration—Calibration is established upon satisfactory completion of a reference oil test sequence that meets
established reference oil targets.
9.4.1 Each calibration sequence consists of three operationally valid and statistically acceptable reference oil tests.
D7452 − 24
9.4.2 When a calibration is being performed after the twentieth non-reference oil test on a previously calibrated test stand, or after
three months since the last satisfactory reference oil test, perform a single operationally valid and statistically acceptable reference
oil test.
9.4.2.1 The calibration sequence consists of the new test and the last two calibration tests performed.
9.4.3 Each operationally valid test is considered statistically acceptable if the end of test pinion coast side scoring meets the
Shewhart limits as published by the Test Monitoring Center. Specific Shewhart limits are defined for each gear batch and reference
oil combination.
9.4.3.1 Repeat any operationally valid calibration test in the calibration sequence with an end-of-test pinion coast side scoring
value exceeding the Shewhart limits until acceptable pinion scoring results are achieved.
9.5 New Test Stand Calibration—A new test stand is considered calibrated upon completion of satisfactory reference oil tests
(assigned by the TMC) that meet established reference oil targets.
9.5.1 New test stand inspection by the TMC is also required to complete the calibration.
9.6 In-Service Stand Calibration—Calibrate previously referenced test stands according to instructions provided in 9.4; that is,
after every twentieth non-reference oil test, or after three months since the last acceptable reference oil test sequence.
9.6.1 Also, if any of the special circumstances described below are involved, calibrate with a new four reference oil test calibration
sequence including a new discrimination oil run:
9.6.1.1 After a test stand is moved, or
9.6.1.2 After changing axle batches, or
9.6.1.3 After changing throttle settings, or
9.6.1.4 After changing torque settings, or
9.6.1.5 After major computer changes, or
9.6.1.6 After a test not conforming to this test method was run in the stand since the last acceptable reference test, or
9.6.1.7 After 6 months since the last valid L42 calibration test, or
9.6.1.8 After two reference oil calibration attempts are made resulting in the end-of-test pinion coast side scoring not meeting the
Shewhart limits as published by the Test Monitoring Center, or the tests are statistically unacceptable or operationally invalid.
9.6.2 If a new three reference oil test calibration sequence is being attempted, there shall not be more than five attempts between
the first and last run numbers.
9.6.2.1 If the discrimination oil test (see 9.7) is also required, there shall not be more than eight attempts between the first and
last run numbers.
9.7 Discrimination Oil Testing—Conduct a discrimination oil test on the test stand every six months from the completion of the
last test in the calibration sequence or after four calibration sequences.
9.7.1 Discrimination Oils approved by the L-42 Surveillance Panel are oils that demonstrate lower-performance levels compared
to that of regular TMC reference oils.
9.7.2 The end-of-test pinion coast side scoring value of the discrimination oil test shall be a minimum of twice the average value
of the three acceptable reference oil tests for the discrimination test to be considered acceptable. The discrimination oil test may
be conducted at any time during the calibration sequence. If the discrimination oil test isconducted at the end of the calibration
D7452 − 24
sequence and a second discrimination oil test is needed, this second discrimination oil test, if acceptable, will count as 1 of the
20 non-reference oil tests. Repeat the complete calibration sequence (the three reference oil tests and the discrimination oil test)
if both discrimination oil tests do not meet the above requirements.
9.8 Correction Factor—When using TMC Reference Oil 117 for stand calibration, add 6 % to the pinion scoring result and add
4 % to the ring scoring result. Report both the rated scoring and the corrected scoring in the space provided in the test report.
9.9 Reference Test Frequency—The test stand calibration period is defined as three months or 20 tests, whichever occurs first. It
begins on the completion date of an operationally and statistically acceptable reference oil test series as determined by the TMC.
Any test started on or before the stand calibration expiration date is defined to have been run on a calibrated stand.
9.9.1 When a test stand is out of calibration for a period of six months or longer, renumber the stand, and follow LTMS guidelines
for new stand introduction.
9.9.2 Report modification of test stand apparatus or completion of any nonstandard test on a calibrated test stand to the TMC
immediately.
9.10 Assign a sequential test run number to every test start on any test stand before testing begins. All tests, including aborted starts
and operationally invalid tests, shall retain their test number.
9.11 Instrument Calibration—Calibrate the wheel and pinion speed measuring systems and axle oil temperature control system at
least every six months or 60 non-reference oil tests, whichever occurs first. Perform an instrument calibration against a known
standard traceable to either the National Institute of Standards and Technology (NIST) or to a physical constant.
9.11.1 Prior to each reference oil test sequence, calibrate the pinion torque measuring device using a dead weight calibration.
Perform the calibration on both the positive (drive) and negative (coast) side of zero.
9.11.2 Engine Throttle Body Calibration—Calibrate prior to every calibration sequence.
9.11.2.1 Warm the engine up until the coolant temperature is greater than 150 °F (65.6 °C).
9.11.2.2 Connect a voltmeter to the throttle position sensor (TPS) to measure the TPS voltage sent to the engine ECM.
9.11.2.3 Adjust the Foxboro/Jordon zero potentiometer to close the throttle until engine idle speed is at 675 r ⁄min 6 75 r ⁄min.
Record the TPS voltage.
9.11.2.4 Set the throttle controller at 100 % output. Adjust the Foxboro/Jordon “span” potentiometer until the observed TPS
voltage is 1.3 V 6 0.1 V higher than the voltage recorded in 9.11.2.3.
10. Procedure for Conducting the Test
10.1 The test axles are batch specific. See TMC Memo 94-200 for approved gear batches and test targets.
10.2 Gear Conditioning—All ramp targets should be reached in approximately five min. Minimize drive torque to prevent drive
side scoring.
10.2.1 Conditioning 1:
10.2.1.1 Set the axle oil temperature control equipment at a set point of 225 °F (107.2 °C). When the axle oil temperature reaches
set point, maintain the temperature within 225 °F 6 10 °F (107.2 °C 6 5.6 °C) until conditioning is complete.
10.2.1.2 Shift Gears—With the engine at operating temperature set the engine idle speed to 700 r ⁄min 6 200 r ⁄min (73 rad ⁄s 6
21 rad ⁄s). Prior to shifting gears set the engine speed manual output to achieve approximately 2000 r ⁄min (209 rad ⁄s). With no
torque on the dynamometers smoothly shift the transmission through the gears (without bucking the axle) allowing the engine to
recover to approximately 1500 r ⁄min (157 rad ⁄s) between shifts. Shift through the gears until 1:1 ratio (4th gear) is reached.
10.2.1.3 Ramp & Condition—Set data acquisition to record pinion torque, wheel speed and axle temperature at a minimum of 1
D7452 − 24
Hz. Accelerate both wheels to a speed of 575 r ⁄min 6 5 r ⁄min (60 rad ⁄s 6 0.5 rad ⁄s) (pinion speed 2352 r ⁄min 6 20 r ⁄min
(246 rad ⁄s 6 2 rad ⁄s)). Apply a dynamometer excitation to achieve a pinion torque of 60 lbf-ft 6 20 lbf-ft (81 N·m 6 27 N·m).
When both conditions are met, begin conditioning phase 1 and maintain for 10 min 6 0.5 min. At the end of this steady state
operation lock dynamometer excitation at the output necessary to achieve 60 lbf-ft (81 N·m). Immediately proceed to 10.2.2.
10.2.2 Conditioning 2—Set data acquisition to record pinion torque and wheel speed at a minimum of 10 Hz and axle temperature
at a minimum of 1 Hz. While maintaining the fixed dynamometer excitation, slowly cycle the wheel speed from 575 r ⁄min 6
20 r ⁄min (60 rad ⁄s 6 0.5 rad ⁄s) to 385 r ⁄min 6 20 r ⁄min (40 rad ⁄s 6 0.5 rad/s). Maintain the fixed dynamometer excitation
settings and control throttle movement slowly enough to maintain pinion torque values sufficient to properly condition the drive
and coast side of the axle. Complete four cycles then immediately proceed to 10.2.3. The total time of the four cycles shall not
exceed 5 min.
NOTE 1—It is believed that if the shape of both drive and coast segments of Conditioning 2 and Conditioning 4 are flat topped in nature (without any
spikes in the acceleration or deceleration torque that would indicate a shock) the torque values found from this data stream will be a better representation
of the gear conditioning.
10.2.3 Conditioning 3:
10.2.3.1 Maintain the axle oil temperature control at 225 °F 6 10 °F (107.2 °C 6 5.6 °C).
10.2.3.2 Ramp & Condition—Set data acquisition to record pinion torque, pinion speed and axle temperature at a minimum of
1 Hz. Accelerate both wheels to a wheel r/min speed of 815 r ⁄min 6 5 r ⁄min (85 rad ⁄s 6 0.5 rad ⁄s). Apply a dynamometer
excitation to achieve a pinion torque of 70 lbf-ft 6 20 lbf-ft (95 N·m 6 27 N·m). When both conditions are met, maintain for
20 min 6 0.5 min. At the end of this steady state operation lock dynamometer excitation at the output necessary to achieve 70 lbf-ft
(95 N·m). Immediately proceed to 10.2.4.
10.2.4 Conditioning 4:
10.2.4.1 Set data acquisition to record pinion torque and wheel speed at a minimum of 10 Hz and axle temperature at a minimum
of 1 Hz. While maintaining the fixed dynamometer excitation, slowly cycle the wheel speed from 815 r ⁄min 6 20 r ⁄min (85 rad ⁄s
6 2 rad ⁄s) to 670 r ⁄min 6 20 r ⁄min (70 rad ⁄s 6 2 rad ⁄s). Maintain the fixed dynamometer excitation settings and control throttle
movement slowly enough to maintain pinion torque values sufficient to properly condition the drive and coast side of the axle.
Complete four cycles then immediately proceed to 10.2.4.2. The total time of the four cycles shall not exceed 5 min.
10.2.4.2 Shift transmission into neutral to avoid additional coast side conditioning. Bring engine r/min down to idle.
10.2.5 Inspection 1—(Warning—Differential is extremely hot. Hot oil can produce vapors.)
10.2.5.1 Inspect ring gear and report approximate drive and coast percent scoring. Inspection should take approximately 5 min.
Make an effort to minimize the time spent during the inspection.
10.3 Shock Series 1:
10.3.1 Shock Series 1 Preparation:
10.3.1.1 Set the engine speed manual output to achieve approximately 2000 r ⁄min (209 rad ⁄s). prior to shifting gears. With no load
on the dynamometers smoothly shift the transmission through the gears (without bucking the axle) allowing the engine to recover
to approximately 1500 rpm (157 rad ⁄s) between shifts. Shift through the gears until 1:1 ratio (4th gear) is reached. Set temperature
control set point to 200 ºF (93.3 °C).
10.3.1.2 Set data acquisition to record pinion torque, wheel speed and axle temperature at a minimum of 1 Hz. Slowly accelerate
the driveline until wheel speed is 530 r ⁄min 6 5 r ⁄min (55 rad ⁄s 6 0.5 rad ⁄s) (pinion speed 2168 r ⁄min 6 20 r ⁄min (227 rad ⁄s 6
2 rad ⁄s)). Apply dynamometers excitation to maintain 50 lbf-ft 6 10 lbf-ft (68 N·m 6 14 N·m) pinion torque.
10.3.1.3 Differential housing oil temperature shall be 200 °F 6 5 °F (93.3 °C 6 2.8 °C) at the start of Shock Series 1. See A5.2.2.2
for L-42 Canadian Version test.
D7452 − 24
10.3.1.4 Once pinion speed, pinion torque, and axle lubricant temperature reach steady state, lock dynamometer excitation at the
output necessary to maintain 50 lbf-ft 6 10 lbf-ft (68 N·m 6 14 N·m), turn off axle oil temperature control, and proceed
immediately to 10.3.2.
10.3.2 Shock Series 1 Procedure:
10.3.2.1 Turn the axle cooling water off after the ramp-up of Shock Series 1. Ensure that the axle cooling water is off during the
shocks. See A5.2.2.3 for L-42 Canadian Version test.
10.3.2.2 Record axle oil temperature at the start of Shock Series 1 on the appropriate form. Maintain the fixed dynamometer
excitation until the transmission is shifted into neutral at end of Shock Series 1 in 10.3.2.3.
10.3.2.3 Set data acquisition to acquire pinion torque data at a minimum of 100 Hz, wheel speed at a minimum of 10 Hz and axle
temperature at a minimum of 1 Hz While maintaining the fixed dynamometer excitation begin cycling the wheel speed from
530 r ⁄min 6 20 r ⁄min (55 rad ⁄s 6 2 rad ⁄s) to 1050 r ⁄min 6 20 r ⁄min (110 rad ⁄s 6 2 rad ⁄s). Complete five cycles, ending by
accelerating the engine to bring the pinion torque back to near 0, then proceed to 10.3.2.4.
10.3.2.4 Shift transmission into neutral to avoid additional coast side conditioning. Bring engine speed down to idle.
10.4 Inspection 2—(Warning—Differential is extremely hot. Hot oil can produce vapors.)
10.4.1 Inspect ring gear and report approximate drive and coast percent scoring. Inspection should take approximately 5 min.
Make every effort to minimize the time spent during the inspection to maintain the axle temperature. Do not cool the axle at the
end of Shock Series 1. Ensure the cooling water remains turned off for the remainder of the test. Table A5.1 shows alternative test
versions.
10.5 Shock Series 2:
10.5.1 Shock Series 2 Preparation:
10.5.1.1 If the axle oil temperature is greater than 280 ºF (137.8 ºC) after Inspection 2, allow the axle oil temperature to cool
(without cooling water) until axle oil temperature is less than or equal to 280 ºF (137.8 ºC) before shifting transmission through
the gears. If the axle oil temperature is less than or equal to 280 ºF (137.8 ºC) after Inspection 2, proceed immediately to 10.5.1.2.
10.5.1.2 Set the engine speed manual output to achieve approximately 2000 r ⁄min (209 rad ⁄s). prior to shifting gears. With no
torque on the dynamometers smoothly shift the transmission through the gears (without bucking the axle) allowing the engine to
recover to approximately 1500 rpm (157 rad ⁄s) between shifts. Shift through the gears until 1:1.67 ratio (3rd gear) is reached.
10.5.1.3 Set data acquisition to record pinion torque, wheel speed and axle temperature at a minimum of 1 Hz. Slowly accelerate
the driveline until wheel speed is 530 r ⁄min 6 5 r ⁄min (55 rad ⁄s 6 0.5 rad ⁄s) (pinion speed 2168 r ⁄min 6 20 r ⁄min (227 rad ⁄s 6
2 rad ⁄s)). Apply dynamometers excitation to achieve 70 lbf-ft 6 10 lbf-ft (95 N·m 6 14 N·m) pinion torque. When steady state
operation is achieved lock dynamometer excitation at the output necessary to maintain 70 lbf-ft 6 10 lbf-ft (95 N·m 6 14 N·m).
10.5.1.4 Record axle oil temperature at the start of Shock Series 2 on the appropriate form. Axle oil temperature shall be less than
or equal to 280 ºF (137.8 ºC) at the start of Shock Series 2. See A5.2.2.4 for L-42 Canadian Version test.
10.5.1.5 Set data acquisition to acquire pinion torque data at a minimum of 100 Hz, wheel speed at a minimum of 10 Hz and axle
temperature at a minimum of 1 Hz While maintaining the fixed dynamometer excitation begin cycling the wheel speed from
530 r ⁄min 6 20 r ⁄min (55 rad ⁄s 6 2 rad ⁄s) to 630 r ⁄min 6 20 r ⁄min (66 rad ⁄s 6 2 rad ⁄s). Complete ten cycles, ending by
accelerating the engine to bring the pinion torque back to near 0, then proceed to 10.5.1.6.
10.5.1.6 Shift transmission into neutral to avoid additional coast side conditioning. Bring engine speed down to idle.
10.5.1.7 Record end of test time and test minutes in the appropriate test fields.
10.6 Tear Down Procedure—(Warning—The axle is very hot. Use caution.)
D7452 − 24
10.6.1 Disconnect dynamometers and drive shafts. Perform end of test procedures.
10.6.2 Check backlash in four equally spaced locations and record measurements on the appropriate form.
10.6.3 Disassemble axle for rating of ring and pinion.
10.6.4 Clean ring and pinion with cleaning solvent (see 7.2) and dry.
11. Determination of Test Results
11.1 Part Rating:
11.1.1 Rate and report both drive and coast side of pinion and ring gear for percent of total tooth area that exhibits scoring, see
ASTM Distress Rating Manual 21 (formerly CRC Manual 21). Compare the percent scoring for the non-reference oil tests to the
percent scoring for the three most recent acceptable reference oil tests.
11.1.2 For a valid rating ensure that the individual rating the test has participated in an ASTM gear rater calibration workshop
within the previous twelve months.
11.2 A non-reference oil test that has not been run in a calibrated test stand or not conducted on approved hardware or both is
considered non-interpretable. Note on the cover page of the test report that the test is non-interpretable and that it has not been
conducted in a valid manner in accordance with the test method.
11.3 Reference oil tests, other than a discrimination oil test, and non-reference oil tests that exhibit end of test ring coast side
scoring greater than end of test pinion coast side scoring are non-interpretable.
11.4 Consider reference oil tests, other than the discrimination oil tests, and non-reference oil tests that exhibit drive side scoring
non-interpretable.
11.5 Test Validity—The test is determined to be operationally valid if the percent deviation of the critical operating parameters and
number of shutdowns are within the limits specified and defined in Annex A8.
11.6 Round test results according to Practice E29.
12. Interpretation of Operational Data
12.1 Data Stream Interpretation—Figs. A6.11-A6.21 are required in the final test report. Examples shown are meant to display
all data collected and optimize the resolution of the data. The X and Y axis may be rescaled to achieve this.
12.1.1 Lubricant Temperature:
12.1.1.1 The initial oil temperature for each test sequence shall consist of the average of the first 5 s of data during the sequence.
12.1.1.2 The maximum oil temperature for each test sequence is the single maximum value experienced during the sequence.
12.1.1.3 Referring to Fig. A6.21, plot all data collected from the start of Conditioning 1 to the end of Shock Series 2. Use the X
axis as the elapse time data.
12.1.2 Wheel Speeds:
12.1.2.1 During Conditioning 1, see Fig. A6.11 location (A) and Conditioning 3, see Fig. A6.12 location (D), the reported wheel
speeds shall be the average over the steady-state sequence.
12.1.2.2 Referring to Figs. A6.11 and A6.12, during Conditioning 2 or 4, the value of the maximum and minimum single scan
conditioning 2 and 4 wheel speeds are located at (B -B and C -C ) and (E -E and F -F ) respectively. For both conditioning 2
1 3 1 4 1 3 1 4
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and 4, independently report the maximum, minimum, and average of the single scan maximum speeds and the maximum,
minimum, and average of the single scan minimum speeds by including all peaks and valleys not connected to a steady state
operating condition phase.
12.1.2.3 Referring to Fig. A6.13, during Shock Series 1, the value of the maximum and minimum single scan Shock Series 1 wheel
speeds are to be found at locations (G -G ) and (H -H ) respectively. Report the maximum, minimum, and average of the single
1 5 1 4
scan maximum speeds and the maximum, minimum, and average of the single scan minimum speeds by including all peaks and
valleys not connected to a steady state operating condition phase.
12.1.2.4 Referring to Fig. A6.14, during Shock Series 2, the value of the maximum and minimum single scan Shock Series 2 wheel
speeds are to be found at locations (I -I ) and (J -J ) respectively. Report the maximum, minimum, and average of the single scan
1 10 1 9
maximum speeds and the maximum, minimum, and average of the single scan minimum speeds by including all peaks and valleys
not connected to a steady state operating condition phase.
12.1.3 Pinion Torque Conditioning 1–4:
12.1.3.1 During Conditioning 1, see Fig. A6.15 location (K) and Conditioning 3, see Fig. A6.16 location (N), the reported pinion
torque is the average torque over the steady state sequence.
12.1.3.2 Refer to Fig. A6.17, Conditioning 2 pinion torque, and Fig. A6.18, Conditioning 4 pinion torque. Locations (L -L ) and
0 7
locations (M -M ) represent the zero line crossings for the pinion torque. The drive side gear contact segments are between points
0 7
1 and 2, 3 and 4, and 5 and 6, and 7 and beyond. The coast side gear contact segments are between points 0 and 1, 2 and 3, 4 and
5 and 6 and 7.
12.1.3.3 Referring to Figs. A6.17 and A6.18, Conditioning 2 pinion torque and conditioning 4 pinion torque, the maximum and
minimum single scan conditioning 2 and 4 pinion torque values are located at (B -B and C -C ) and (E -E and F -F )
1 3 1 4 1 3 1 4
respectively. For both conditioning 2 and 4, independently report the maximum, minimum, and average of the single scan
maximum pinion torques and the maximum, minimum, and average of the single scan minimum pinion torques by including all
peaks and valleys not connected to a steady state operating condition phase. Ignore the drive side gear contact segments beyond
zero crossings 7 since their stop times are not well defined.
12.1.4 Pinion Torque—Shock Series 1:
12.1.4.1 Referring to Fig. A6.19, the zero pinion torque crossings (O -O ) are located where the pinion torque value crosses zero.
0 9
The coast side gear contact segments are between points 0 and 1, 2 and 3, 4 and 5, 6 and 7, and 8 and 9. The drive side gear contact
segments are between points 0 and prior, 1 and 2, 3 and 4, 5 and 6, and 7 and 8.
12.1.4.2 Referring to Fig. A6.19, during Shock Series 1, the value of the maximum and minimum single scan Shock Series 1
pinion torques is to be found at locations (P -P ) and (Q -Q ) respectively. Report the maximum, minimum, and average of the
1 5 1 5
single scan maximum pinion torques and the maximum, minimum, and average of the single scan minimum pinion torques.
12.1.4.3 Calculate and report the maximum, minimum, and average drive side gear contact segment time. Calculate and report the
maximum, minimum, and average coast side gear contact segment time. For these time calculations, ignore the first drive side
segment and the last coast side segment since zero crossings are not well defined.
12.1.5 Pinion Torque—Shock Series 2:
12.1.5.1 Referring to Fig. A6.20, the zero pinion torque crossings (R -R ) are located where the pinion torque value crosses zero.
0 19
The coast side gear contact segments are between points 0 and 1, 2 and 3, 4 and 5, 6 and 7, 8 and 9, 10 and 11, 12 and 13, 14
and 15, 16 and 17, and 18 and 19. The drive side gear contact segments are between points 0 and prior, 1 and 2, 3 and 4, 5 and
6, 7 and 8, 9 and 10, 11 and 12, 13 and 14, 15 and 16, and 17 and 18.
12.1.5.2 Referring to Fig. A6.20, during Shock Series 2, the value of the maximum and minimum single scan Shock Series 2
pinion torques is to be found at locations (S -S ) and (T -T ) respectively. Report the maximum, minimum, and average of the
1 10 1 10
single scan maximum pinion torques and the maximum, minimum, and average of the single scan minimum pinion torques.
12.1.5.3 Calculate and report the maximum, minimum, and average drive side gear contact segment time. Calculate and report the
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maximum, minimum, and average coast side gear contact segment time. For these time calculations, ignore the first drive side
segment and the last coast side segment since zero crossings are not well defined.
12.1.6 Total Test Time:
12.1.6.1 Calculate and report total test time starting from the beginning of Conditioning 1 to the end of Shock 2.
13. Report
13.1 For reference oil results, use the standardized report form set available from the ASTM TMC.
NOTE 2—Report the non-reference oil test results on these same forms if the results are intended to be submitted as candidate oil results against a
specification.
13.1.1 Fill out the report forms according to the formats shown in the data dictionary.
13.1.2 Transmit results to the TMC within 5 working days of test completion.
13.1.3 Transmit the results electronically as described in the ASTM Data Communications Committee Test Repo
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