INSPECTION AND ANALYSIS OF FAILED TRANSMISSIONS INTERIM REPORT TFLRF No. 399 by Adam C. Brandt Edwin A. Frame U.S. Army TARDEC Fuels and Lubricants Research Facility Southwest Research Institute ® (SwRI ® ) San Antonio, TX for U.S. Army TARDEC Force Projection Technologies Warren, Michigan Contract No. DAAE-07-99-C-L053 (WD51) Approved for public release: distribution unlimited June 2009 ADA
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INSPECTION AND ANALYSIS OF FAILED TRANSMISSIONS · Three Allison Transmission Incorporated (ATI) 2500-SP transmissions failed in service OCONUS, and were shipped to US Army TARDEC
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INSPECTION AND ANALYSIS OF FAILED TRANSMISSIONS
INTERIM REPORT TFLRF No. 399
by Adam C. Brandt Edwin A. Frame
U.S. Army TARDEC Fuels and Lubricants Research Facility Southwest Research Institute® (SwRI®)
San Antonio, TX
for U.S. Army TARDEC
Force Projection Technologies Warren, Michigan
Contract No. DAAE-07-99-C-L053 (WD51)
Approved for public release: distribution unlimited
June 2009
ADA
Disclaimers
The findings in this report are not to be construed as an official Department of the Army position unless so designated by other authorized documents. Trade names cited in this report do not constitute an official endorsement or approval of the use of such commercial hardware or software.
DTIC Availability Notice Qualified requestors may obtain copies of this report from the Defense Technical Information Center, Attn: DTIC-OCC, 8725 John J. Kingman Road, Suite 0944, Fort Belvoir, Virginia 22060-6218.
Disposition Instructions Destroy this report when no longer needed. Do not return it to the originator.
INSPECTION AND ANALYSIS OF FAILED TRANSMISSIONS
INTERIM REPORT TFLRF No. 399
by Adam C. Brandt Edwin A. Frame
U.S. Army TARDEC Fuels and Lubricants Research Facility
Southwest Research Institute® (SwRI®) San Antonio, TX
Approved for public release: distribution unlimited
June 2009 Approved by: Steven D. Marty, P.E., Director U.S. Army TARDEC Fuels and Lubricants Research Facility (SwRI®)
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REPORT DOCUMENTATION PAGE Form Approved OMB No. 0704-0188
Public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing this collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden to Department of Defense, Washington Headquarters Services, Directorate for Information Operations and Reports (0704-0188), 1215 Jefferson Davis Highway, Suite 1204, Arlington, VA 22202-4302. Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to any penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number. PLEASE DO NOT RETURN YOUR FORM TO THE ABOVE ADDRESS. 1. REPORT DATE (DD-MM-YYYY) 30-01-2009
2. REPORT TYPE Interim Report
3. DATES COVERED (From - To) November 2008 – January 2009
4. TITLE AND SUBTITLE Inspection and Analysis of Failed Transmissions
5a. CONTRACT NUMBER DAAE07-99-C-L053 WD 51
5b. GRANT NUMBER
5c. PROGRAM ELEMENT NUMBER
6. AUTHOR(S) Brandt, A.C. and Frame, E. A.
5d. PROJECT NUMBER SwRI 08.03227.51
5e. TASK NUMBER WD 51
5f. WORK UNIT NUMBER
7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) 8. PERFORMING ORGANIZATION REPORT NUMBER
U.S. Army TARDEC Fuels and Lubricants Research Facility (SwRI®) Southwest Research Institute® P.O. Drawer 28510 San Antonio, TX 78228-0510
U.S. Army RDECOM U.S. Army TARDEC 11. SPONSOR/MONITOR’S REPORT Force Projection Technologies NUMBER(S) Warren, MI 48397-5000 12. DISTRIBUTION / AVAILABILITY STATEMENT Approved for public release; distribution unlimited
13. SUPPLEMENTARY NOTES
14. ABSTRACT Three Allison Transmission Incorporated (ATI) 2500-SP transmissions failed in service OCONUS, and were shipped to US Army TARDEC Fuels and Lubricants Research Facility for tear down and inspection. Each transmission was completely disassembled and components inspected and rated in an effort to determine the overall cause of failure. Used fluid samples were collected from each transmission and analyzed to classify the types of fluid that were in use during failure. Upon completion of work, a parts inspection meeting was hosted at Southwest Research Institute for representatives from TARDEC and ATI.
15. SUBJECT TERMS
16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF ABSTRACT
18. NUMBER OF PAGES
19a. NAME OF RESPONSIBLE PERSON
a. REPORT Unclassified
b. ABSTRACT Unclassified
c. THIS PAGE Unclassified
Unclassified
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19b. TELEPHONE NUMBER (include area code)
Standard Form 298 (Rev. 8-98) Prescribed by ANSI Std. Z39.18
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EXECUTIVE SUMMARY
Three Allison Transmission Incorporated (ATI) 2500-SP transmissions were shipped to the US
Army TARDEC Fuels and Lubricants Research Facility for failure analysis. Transmissions were
removed from RG31 Mine Resistant Ambush Protected (MRAP) vehicles that were reported to
have little to no acceleration. All vehicles were located OCONUS. Information was also
provided that failed units could have been changed over to a MIL-PRF-2104 oil during service.
The following transmissions arrived for teardown and inspection:
• SN 6310824455 – Date Code E7KO2
• SN 6310817160 – Date Code 07JO4
• SN 6310817719 – Date Code 07JO5
All transmissions were completely disassembled, and internal components were visually
inspected by TFLRF staff and ATI certified technicians. From the initial visual inspection, it was
evident due to the discoloration of the torque converters and melted plastic speed sensors, that
the transmissions had experienced high temperatures. The condition of all driveline critical
components were rated based on comparison with new, unused components. In addition, torque
converters were cut open and internal components were inspected. Fluid samples collected prior
to disassembly were analyzed to determine their characteristics in an effort to determine if the
fluid was consistent with used engine oils or that of transmission fluids.
A damaged or malfunctioning stator assembly was indentified within each transmissions torque
converter. The stator assembly is used to redirect the fluid leaving the turbine back into the pump
at high differential pump and turbine speeds creating torque multiplication. In an event of a
freewheeling stator, the stator cannot redirect the fluid resulting in little to no acceleration of the
vehicle. From the used oil analysis, no evidence of engine oils were found to be present. Results
from the oil analysis were found to be consistent to that of used Dexron or TES-295 automatic
transmission fluids.
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A parts inspection meeting was held for representatives from TARDEC and ATI. Parts were
inspected, and discussions were held regarding the MRAP vehicle and transmission application,
as well as details regarding the overall failure. It was the opinion of the ATI representatives that
the problems experienced were not a result of fluid incompatibility. This supports findings by
TFLRF. In addition, ATI requested access to two of the three used torque converters for future
analysis.
FOREWORD/ACKNOWLEDGMENTS
The U.S. Army TARDEC Fuels and Lubricants Research Facility (TFLRF) located at Southwest
Research Institute (SwRI®), San Antonio, Texas, performed this work during the period
November 2008 through January 2009 under Contract No. DAAE-07-99-C-L053. The U.S.
Army Tank-Automotive RD&E Center, Petroleum and Water Business Area, Warren, Michigan
administered the project. Mr. Luis Villahermosa (AMSTA-RBFF) served as the TARDEC
contracting officer’s technical representative.
The authors would like to acknowledge the contribution of the TFLRF technical support staff,
consultation from SwRI technical advisor Ray Townsend and US Army TARDEC Fuels and
Lubricant Research Facility Director Steve Marty, as well as administrative and report-
processing support provided by Dianna Barrera.
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TABLE OF CONTENTS
Section Page
EXECUTIVE SUMMARY ........................................................................................................................................ V
FOREWORD/ACKNOWLEDGMENTS ............................................................................................................... VI
LIST OF TABLES ................................................................................................................................................. VIII
LIST OF FIGURES ............................................................................................................................................... VIII
ACRONYMS AND ABBREVIATIONS ................................................................................................................. IX
1.0 INTRODUCTION AND BACKGROUND .................................................................................................... 1
ASTM American Society for Testing Materials ATI Allison Transmission Incorporated avg Average Ca Calcium cSt Centistokes Cu Copper Fe Iron FTIR Fourier Transform Infrared ICP Inductively-coupled plasma lb Pound Mg Magnesium MRAP Mine Resistant Ambush Protected OCONUS Outside the Continental United States P Phosphorus Pb Lead ppm Parts per million SwRI Southwest Research Institute TAN Total acid number TARDEC Tank-Automotive RD&E Center TBN Total base number TFLRF U.S. Army TARDEC Fuels and Lubricants Research Facility Zn Zinc
1
1.0 INTRODUCTION AND BACKGROUND
The US Army TARDEC Fuels and Lubricants Research Facility (TFLRF) received
information on multiple transmission failures occurring in RG31 mine resistant ambush
protected (MRAP) vehicles. All failures occurred in vehicles located OCONUS. Limited
information was available on the description of the failure mode or information regarding
vehicle servicing and maintenance. It was noted that transmission failures occurred with
limited vehicle use, and the possibility existed that failed units could have been filled
with a MIL-PRF-2104 oil. Information regarding the failure description was limited to
vehicles exhibiting little to no acceleration.
Three reportedly failed Allison Transmission Incorporated (ATI) 2500-SP transmissions
were shipped from the OCONUS location to Red River Army Depot in Texarkana, TX
and then forwarded to Stewart and Stevenson LLC located in San Antonio, TX. Each
transmission was disassembled and inspected by Stewart and Stevenson ATI certified
technicians and TFLRF staff. The following is a list of transmissions that were received
and inspected:
• SN 6310824455* – Date Code E7KO2
• SN 6310817160* – Date Code 07JO4
• SN 6310817719* – Date Code 07JO5
*For simplicity, the last three digits of the serial number will be used to refer to each unit.
TFLRF staff’s role was to determine the overall cause of transmission failure, and
determine if failure was attributable to the type of fluid used.
2.0 PROCEDURE
Each transmission was disassembled and inspected by TFLRF staff and ATI certified
technicians at Stewart and Stevenson LLC. Prior to disassembly, used fluid samples were
collected from each transmission drain pan for used oil analysis. Transmissions were then
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completely disassembled, and all components received a detailed visual inspection.
Components of interest were measured and compared to published specs provided by
ATI for new and used components. These components included the torque converter,
main oil pump, shift solenoids, and pressure transducers. After disassembly, all
components were shipped to TFLRF facilities, and all driveline critical components such
as clutch packs and planetary gear sets were then rated based on overall condition as
compared to new components. Torque converters from each unit were cut open in an
effort to determine the condition of the internal stator/one-way clutch assembly, as well
as the lockup friction disk and reaction plate. After the inspection was complete and all
data collected, parts were displayed for inspection by TARDEC and ATI representatives.
3.0 TRANSMISSION COMPONENT INSPECTION
The three transmissions can be split into two groups based on overall internal component
condition. First, SN455 had experienced severe heat, and thus had incurred the most
internal damage resulting in some glazed/burned friction disks and various melted plastic
speed sensors. The second group, comprised of SN719 and SN160, were found to be in
good condition with no major clutch damage or obvious signs of exposure to extreme
heat. In all transmissions, C1 and C4 clutch packs were found to have damage that varied
from none to mild. From the initial inspection, no apparent cause of failure was indicated
based on the condition of the internal components. Findings are listed below by
individual transmission serial number.
SN455
The following is a listing of internal component condition as found during teardown and
inspection on SN455:
• Transmission had experienced high temperatures, evident by the discoloration and
odor of the used fluid when drained.
• All plastic speed sensors had melted housings.
• Plastic debris found in oil pan (attributed to melted sensors).
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• Plastic debris filtering screen in valve body melted and deformed.
• C1 clutch pack had to be forcibly removed from the shaft during disassembly due
to warped steel plates. C1 clutch contained darkened and moderately glazed
friction disks. C4 friction disks had darkening of the inner radius and slightly
polished steel plates. Remaining clutches varied from damage free to some light
darkening.
• Planetary gears and carriers in excellent condition with no pitting or spalling of
teeth.
• Oil pump housing and gears measured within specified tolerances and showed no
visual signs of unusual wear (measured values are presented in Appendix A).
• Torque converter completely blued/blackened with measured endplay outside of
specs.
• Factory installed suction filter had been replaced and magnet was missing
between filter and transmission housing.
• All shift solenoid and temperature sender resistances measured within specs