Service Bulletin – Product

Subject: Endurant HD AT and PACCAR AT Mechatronic Transmission Module (MTM)
Loose Rail Cover Cap Screws
Document Number: TAIB-0994
Updated: April 4, 2022

Date: July 19, 2021

Issue Description:
MTM rail cover cap screws may come loose, leak air, and result in a Rail B or Rail C
fault.
•
•

FC 740 SPN 6145 FMI 0 (Rail B)
FC 760 SPN 6146 FMI 0 (Rail C)

Containment/Corrective Action:
The following manufacturing changes have been applied:
1. July 29, 2019 - 100% visual inspection to verify Loctite was applied to cap
screws and rail covers were fully seated.
2. August 23, 2019 - rail cover cap screw torque was increased to 12.5 Nm.
3. September 4, 2019 - implemented refined machining process and sorting at
manufacturing plants.
4. Julian Date Build Date Code etched into MTM Housing:

Vender MTM Serial Number Decoder from example above
• 12S18341102918 = 2018
• 12S18341102918 = 341st day of 2018 (December 7, 2018)
Affected Models/Population: Endurant HD AT and PACCAR AT MTM’s and
transmissions built prior to above Containment / Corrective Actions.

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Service Bulletin – Product
Field Strategy:
1. Upon removal of the MTM for inspection from an Active or Inactive Rail B or
Rail C Fault noted in the issue description above, and sealing O-ring is
protruding, the MTM must be replaced. For any Active or Inactive Rail B or Rail
C Fault follow the troubleshooting guide TRTS0950.
2. For MTM serial number less than 12S19248145012,
o If the MTM is removed for another failure and any loose rail cap screws
are found (no Active or Inactive rail MTM faults) or the sealing O-ring is
not protruding, reference the RRMT0037 Service Procedure. If there are
Active or Inactive codes for any MTM faults and there are no loose rail
capscrews, follow the troubleshooting guide TRTS0950.
Note: RRMT0037 Service Procedure is available in the July 2021
Edition of the Endurant Service Manual (TRSM0950).
o If torque specifications outlined in the service procedure cannot be met
(threads in MTM are stripped) the MTM must be replaced.

3. Pictures of loose cap screws, position, and MTM serial number shall be
documented in the warranty claim.
MTM Rail B and Rail C Identification

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Service Bulletin – Product
MTM Rail Cover Locations

Rail B Rail Cover Loose Cap Screw Identification

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Service Bulletin – Product
Rail C Rail Cover Loose Cap Screw Identification

•
•
•

Perform service procedure ONLY if a rail cap screw is visibly loose.
Pictures, loose screw position, and MTM serial number must be documented in
the warranty claim.
If no loose rail cap screws are visibly verified, no further service is needed.

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Service Bulletin – Product

Rail D
Rail E
Rail C
Rail B

There is one cap screw on Rail C that is not accessible. Do not dissassemble any
other components to access this cap screw. If this cap screw is visibly loose replace
the MTM.

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Service Bulletin – Product
Warranty Information:
Warranty Parts:
• Loctite 262 / Red Eaton part number 71232 (10 ML Tube) or Loctite 243
/ Blue or equivalent - source locally
• ¼” Brass Brush - source locally
• Foam Swab - source locally
Warranty Labor:
• Inspection (0.2 hours)
• Claim Documentation (pictures, cap screw location, and MTM S/N) (0.3
hours)
• Repair Procedure (1.0 hours)
Claim Coding:
• If Rail C Fastener loose is primary, reference Endurant Claim Coding
guidelines for Rail C Fastener loose (whether Rail B and/or C).
•

If the MTM is removed for another failure, no additional claim coding is
required. Code to original reason that the transmission was repaired.

•

If MTM loose fastener repair is completed for a clutch claim and there is no
other transmission failure mode, then reference Endurant Claim Coding
guidelines for Rail C Fastener loose (whether Rail B and/or C).

The material contained in this bulletin is product improvement information. Eaton Corporation is not committed to,
or liable for, canvassing existing products.
FSUD: 2021-FSUD-4277

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