Fault Code 740: Rail B Operation (TRTS0950)

Endurant HD

TRTS0950 EN-US

November 2024 - B

Fault Code 740: Rail B Operation

J1939: SA 3 SPN 6145 FMI 0, 1, 2, 7, 10, 14, 15, 16, 17, 18, 20, 21

Overview

The Mechatronic Transmission Module (MTM) is equipped with solenoids to direct pneumatic flow to actuate shift rails and sensors to monitor rail positions. The Transmission Control Module (TCM) compares the rail command and position to ensure proper rail operation. The solenoids, positions sensors and shift rails are located in the MTM and connected to the TCM at the 74-Way Transmission Harness Connector.

Detection

The TCM monitors the Rail B Operation. If a system failure is detected, the fault is set active.

Conditions to Set Fault Code Active

FMI 0 – Data Valid But Above Normal (Most Severe): Rail B is unable to disengage the Secondary Drive Gear, move aft, for 2 seconds.

FMI 1 – Data Valid But Below Normal (Most Severe): Rail B is unable to disengage the Primary Drive Gear, move fore, for 2 seconds.

FMI 2 – Data Erratic: Rail B is unable to move the synchronizer to neutral during a rail calibration.

FMI 7 – Mechanical System Not Responding: Rail B is unable move from neutral toward the Secondary Drive Gear for 2 seconds.

FMI 10 – Abnormal Rate of Change: Rail B is unable to confirm low rail speed velocity during a rail calibration.

FMI 14 – Special Instructions: Rail B is unable to move from neutral toward the Primary Drive Gear for 2 seconds.

FMI 15 – Data Valid but Above Normal (Least Severe): Rail B is unable to fully engage the Secondary Drive Gear for 2 seconds.

FMI 16 - Data Valid but Above Normal (Moderately Severe): Rail B is unable to achieve neutral from the Secondary Drive Gear for 2 seconds.

FMI 17 – Data Valid but Below Normal (Least Severe): Rail B is unable to fully engage the Primary Drive Gear for 2 seconds.

FMI 18 – Data Valid but Below Normal (Moderately Severe): Rail B is unable to achieve neutral from the Primary Drive Gear for 2 seconds.

FMI 20 – Data Drifted High: Rail B travel was greater than expected during a rail calibration.

FMI 21 – Data Drifted Low: Rail B travel was less than expected during a rail calibration.

Fallback

FMI 0:

Amber warning lamp on
Rail B engagement of the synchronizer into neutral prohibited
Rail B engagement of the Primary Drive Gear prohibited

FMI 1:

Amber warning lamp on
Rail B engagement of the synchronizer into neutral prohibited
Rail B engagement of the Secondary Drive Gear prohibited
PTO Mode prohibited

FMI 2, 10, 20, 21:

Amber warning lamp on
Non neutral modes prohibited
PTO Mode prohibited
If the vehicle is moving
- Red stop lamp on

FMI 7, 15:

Amber warning lamp on
Rail B engagement of the Secondary Drive Gear prohibited
PTO Mode prohibited
If vehicle is moving and no start gear available
- Red stop lamp on

FMI 14, 17:

Amber warning lamp on
Rail B engagement of the Primary Drive Gear prohibited
If vehicle is moving and no start gear available
- Red stop lamp on

FMI 16, 18:

Amber warning lamp on
Rail B engagement of the synchronizer into neutral prohibited
If vehicle is moving and no start gear available
- Red stop lamp on

Conditions to Set Fault Code Inactive

FMI 0, 1, 7, 14, 16, 18: Condition no longer exists

FMI 2, 10, 20, 21: Successful rail calibration

FMI 15, 17: Key cycle

Possible Causes

All FMIs:

MTM
- Contamination from vehicle air system
- Air leaks
- Rail B Fore Solenoid – internal failure
- Rail B Aft Solenoid – internal failure
- Rail B Position Sensor – in range internal failure
- Rail B shift cylinder – stuck piston or damaged seals
- Rail B shift rail or yoke – broken
Internal transmission
- Rail B Synchronizer
- Secondary Drive Gear
- Primary Drive Gear

Additional Tools

Endurant HD Service Manual TRSM0950
Rail B Synchronizer Engagement Tool - RR1088TR

Component Identification


1. Transmission Control Module (TCM) Cover 2. Transmission Control Module (TCM) 3. 74-Way Transmission Harness Connector (MTM-side) 4. 74-Way Transmission Harness Connector (TCM-side) 5. Transmission Control Module (TCM) Seal 6. MTM Air Inlet Port

_Graphics/LineArt/TRTS0950_FC511_ComponentID.png

1. Transmission Control Module (TCM) Cover

2. Transmission Control Module (TCM)

3. 74-Way Transmission Harness Connector (MTM-side)

4. 74-Way Transmission Harness Connector (TCM-side)

5. Transmission Control Module (TCM) Seal

6. MTM Air Inlet Port

Fault Code 740 Troubleshooting

Purpose:Check for active or inactive fault codes.

Set vehicle parking brake and chock wheels.
Record the transmission fault codes, FMIs, occurrences, and timestamps from the Service Activity Report created during the Diagnostic Procedure.

If Fault Code 740 FMI 0, 1 is Active or Inactive, Go to Step E

If Fault Code 740 FMI 2, 10, 14, 15, 20, 21 is Active or Inactive, Go to Step B

If Fault Code 740 FMI 7, 16, 17 is Active or Inactive and MTM was not recently installed or replaced, go to TAIB-1006 MTM Solenoid Fault Codes and Vehicle Air System Contamination.

If Fault Code 740 FMI 16, 18 is Active or Inactive and MTM was recently installed or replaced, Go to Step F

If Fault Code 740 FMI 18 is Active or Inactive and MTM was not recently installed or replaced, Go to Step B

NOTICE: Refer to Vehicle Maintenance Recommendations regarding vehicle air system requirements to ensure proper air supply and air quality.

Purpose:Verify condition of the vehicle air system supply line and MTM air inlet port.

Key off.
Refer to OEM guidelines and vent the vehicle air supply line to the MTM.
Refer to OEM guidelines and remove the vehicle air supply line at the MTM.
Inspect the vehicle air supply line and the MTM air inlet port for contamination, moisture, corrosion and/or debris.
Note: Verify the MTM inlet screen is installed and free of contamination and/or debris.

If contamination is found, refer to OEM guidelines for repair or replacement of the vehicle air system. Replace the Mechatronic Transmission Module (MTM) and reference the Lower Countershaft Cover and Inertia Brake Service Procedure for replacement of the Inertia Brake Assembly. Go to Step V

Note: MTM removal and installation requires the transmission to be removed from the vehicle. Reference Endurant HD Service Manual TRSM0950, Transmission Removal Service Procedure.

If no contamination is found, Go to Step C

Purpose:Verify mechanical condition of the Primary and Secondary Drive Gears.

Remove the MTM.
Note: MTM removal and installation requires the transmission to be removed from the vehicle. Reference Endurant HD Service Manual TRSM0950, Transmission Removal Service Procedure.
Inspect the Secondary Drive Gear for excessive fore and aft movement.
Inspect the Primary Drive Gear for excessive fore and aft movement.

If excessive gear movement is evident, inspect for cause of excessive gear movement and repair. Go to Step V

If no excessive gear movement is evident, Go to Step D

Purpose:Verify mechanical condition of the Rail B Synchronizer and clutching teeth.

Inspect the Rail B Synchronizer Sliding Sleeve yoke slot for wear.
Install the Rail B Synchronizer Engagement Tool (RR1088TR).
Note: Reference Appendix, Manually Actuate Rail B Procedure.
Shift the Rail B Synchronizer Sliding Sleeve into neutral (if necessary).
Shift the Rail B Synchronizer Sliding Sleeve into the Secondary Drive Gear engagement position (fore).
Inspect the Primary Drive Gear and synchronizer ring clutching teeth for wear.
Return the Rail B Synchronizer Sliding Sleeve to neutral.
Shift the Rail B Synchronizer Sliding Sleeve into the Primary Drive Gear engagement position (aft).
Inspect the Secondary Drive Gear and synchronizer ring clutching teeth for wear.
Return the Rail B Synchronizer Sliding Sleeve to neutral.

If the Rail B Synchronizer Sliding Sleeve shifts into all three positions and no clutching teeth wear is present, replace Mechatronic Transmission Module (MTM). Go to Step V

If the Rail B Synchronizer Sliding Sleeve does not shift into all three positions or clutching teeth wear is present, reference the Primary Drive Gear Replacement procedure for replacement of the Primary Drive Gear. Replace the Rail B Synchronizer Assembly, Secondary Drive Gear and Mechatronic Transmission Module (MTM). Go to Step V

Purpose:Verify MTM Serial Number.

Record MTM Serial Number (Item 2).

If MTM Serial Number is less then 12S22342093445, go to service bulletin TAIB-0994 MTM Loose Rail Cover Cap Screws .

If MTM Serial Number is equal to or greater than 12S22342093445, Go to Step B

Purpose:Check for Active or Inactive fault codes.

Set vehicle parking brake and chock wheels.
Key off and allow the TCM to perform a complete power down.
Key on.
Connect ServiceRanger.
Select “Service Activity Report”.
Enter information and select “Start Report”.
Note: Fault code and transmission information is downloaded into the report.
Select “Send to Eaton”.
Note: Internet connection is required.
Retrieve and record the transmission fault codes and FMIs and their occurences and timestamps.

If Fault Code 740 FMI 16, 18 is Active or Inactive and MTM was recently installed or replaced, contact Eaton Cummins Automated Transmission Technologies at 1-800-826-HELP (4357) for further diagnostic instructions.

Purpose:Verify repair.

Key off.
Reconnect all connectors and verify that all components are properly installed.
Key on with engine off.
Connect ServiceRanger.
Go to “Fault Codes”.
Select “Clear All Faults”.
Operate vehicle and attempt to reset the fault code or duplicate the previous complaint.
Check for fault codes using ServiceRanger.

If no fault codes set and the vehicle operates properly, test complete.

If Fault Code 740 sets Active during operation, Go to Step A

If a fault code other than 740 sets Active, troubleshoot per the Fault Code Isolation Procedure Index.