Case IH F35 – Transmission Controller / Processor (TCU): Synchronizer Did Not Engage Previous Range After Error Code F20 Or F22

This code indicates that the transmission synchronizer failed to physically shift back into its previous range following a related transmission error (F20 or F22). When this code is triggered, the transmission is disabled to prevent mechanical damage.

• MXM
• MXM 120
• MXM 130
• MXM 140
• MXM 155
• MXM 175
• MXM 190

1. 1

   Attempt recovery by cycling the shuttle lever to try again, or select another range while the tractor is in neutral

2. 2

   Determine if the tractor speed was excessive during the shift. If it was, slow the tractor down and try shifting again

3. 3

   Diagnose and resolve the root cause of preceding error codes F20 or F22, which triggered the F35 code

4. 4

   Enter the 'H' menu mode ('Hd') on the instrument cluster to verify if the transmission processor is detecting any synchronizer movement

5. 5

   Attempt a full recalibration of the transmission if no movement is verified

6. 6

   Perform a pressure test at the appropriate test point on the transmission side cover to verify if the pressure is within the specification of 15-18 bar

1. 1

   Remove the transmission solenoid valve assembly

   Perform this step if pressure is NOT within 15-18 bar.

2. 2

   Clean or replace the solenoid valve

3. 3

   Re-check the pressure

4. 4

   Remove the transmission side cover and inspect the seals of the operating piston for leaks or blow-by

   Perform this if the pressure is still incorrect. Replace the seals if damaged.

5. 5

   Remove the transmission side cover

   Perform this step if pressure IS within 15-18 bar.

6. 6

   Check the synchronizer operating piston to ensure it is not mechanically stuck

7. 7

   Verify that the synchronizer within the transmission is physically able to engage

8. 8

   Inspect the synchronizer potentiometer's operation and its physical linkage for wear, damage, or misalignment

   With the side cover removed. Replace the potentiometer if it is failing to read movement.