Case IH 127 – TRANS (Transmission Controller): C1-2 clutch is not calibrated

The transmission controller has lost the calibration values for the C1-2 clutch pack, or a recent calibration procedure was aborted or failed to complete successfully. Without these values, the transmission cannot properly modulate the engagement of the C1-2 clutch, which can result in harsh shifting or a loss of specific gears.

• MX Magnum
• STX Steiger
• Case IH MX Magnum Series

1. 1

   Check hydraulic fluid temperature to ensure it is at 50 degrees C (122 degrees F) or greater, as calibration will not begin if oil is too cold.

2. 2

   Check for related electrical fault codes (such as 106 or 116) on the TRANS controller, which indicate a hard electrical failure that must be repaired before calibration.

3. 3

   Perform a system pressure check to ensure transmission system pressure is within spec and verify there are no internal leaks at the C1-2 clutch jump tubes or seals.

1. 1

   Prepare for calibration

   Park the tractor on a level surface, apply the parking brake, and ensure the transmission is in neutral.

2. 2

   Warm up hydraulic fluid

   Warm the tractor up until the hydraulic fluid reaches at least 50 degrees C (122 degrees F).

3. 3

   Enter calibration mode

   On MX Magnum models, hold the 'PROG' key on the A-post display while turning the ignition key to the ON position, then navigate to the 'ARM' or 'TRANS' calibration menu. (Alternatively, a dealer can initiate this via the Case IH Electronic Service Tool - EST).

4. 4

   Perform clutch calibration

   Follow the on-screen prompts to begin the clutch calibration. The tractor will automatically cycle through and calibrate the clutches (including C1-2).

5. 5

   Save calibration values

   Once complete, turn the key off and wait 30 seconds before restarting the tractor to ensure the new values are saved to the TRANS controller.

6. 6

   Locate transmission control valve block

   If the calibration fails on the C1-2 clutch, locate the transmission control valve block on the side of the transmission housing.

7. 7

   Inspect C1-2 clutch solenoid and wiring

   Identify the C1-2 clutch solenoid. Inspect the 2-pin wiring harness connector for corrosion, pushed-out pins, or wire chafing.

8. 8

   Test and replace solenoid if defective

   Swap the C1-2 solenoid coil with a neighboring clutch solenoid (e.g., C3-4). Attempt calibration again. If the failure follows the solenoid to the new clutch, the solenoid is defective and must be replaced.