Case IH U129 – Transmission Control Module (TCM) / MTA CCM & APH: Synchronisers not calibrated

The transmission control system lacks the necessary calibration values for the transmission synchronizers. This condition typically occurs if the non-volatile memory (NVM) was recently cleared (such as via the H8 diagnostic menu), if a previous calibration attempt was interrupted or failed, or if transmission components were recently replaced.

• Maxxum 100
• Maxxum 110
• Maxxum 115
• Maxxum 120
• Maxxum 125
• Maxxum 130
• Maxxum 140
• Maxxum 150
• MXU100
• MXU115
• MXU135
• T6.120
• T6.145
• T6.175
• T6000 series
• TS115A
• TS135A

1. 1

   Check transmission fluid temperature (must be warmed up to approximately 60°C; a cold transmission will display a 'CL' warning and prevent calibration)

2. 2

   Check for active short or open circuit fault codes for the clutch or synchronizer solenoids, which will abort the calibration process

3. 3

   Perform safety checks: ensure the tractor is parked away from obstacles, the parking brake is firmly applied, and the ground speed display reads zero

1. 1

   Preparation

   Start the engine and ensure the transmission fluid is up to operating temperature.

2. 2

   Enter Calibration Mode

   Enter the H-menu diagnostic mode (H1 routine) using the tractor's display and transmission buttons.

3. 3

   Position Controls

   Release the clutch pedal. Move the main gear lever to the forward/front position and place the shuttle lever into the forward drive position.

4. 4

   Set Engine Speed

   Set the engine speed to approximately 1200 RPM.

5. 5

   Calibrate Clutches First

   Press the upshift ("bunny") button to begin. The screen will cycle through the clutch packs (C1, C2, C3, C4). For each, press and hold the downshift ("turtle") button until the engine RPM dips and the screen displays "End", then release and proceed to the next clutch.

6. 6

   Calibrate Synchronizers

   After C4 is completed, the screen will display "syn" (synchronize).

7. 7

   Execute Sync

   Press and hold the downshift ("turtle") button. The tractor's computer will automatically take over, raising the engine RPMs and shifting the synchronizers to learn their engagement points.

8. 8

   Save and Exit

   Once the screen displays "End", release the button. Turn the ignition key off to save the new calibration values to the non-volatile memory. Restart the tractor to verify the U129 code has cleared.