Case IH 2405 – Transmission Controller (TCU / Transmission ECU): Range shift synchronizer did not disengage

Occurs when the range change synchronizer fails to physically or electrically uncouple during a gear shift or shuttle shift.

• Optum
• Case IH PUMA Series
• Case IH Steiger Series
• Case IH Quadtrac Series
• Case IH T6000
• Case IH SWB PUMA

1. 1

   Check for other active diagnostic codes for the transmission solenoids or potentiometers (such as 2403, 2412, or voltage codes like 2415/2416) and correct them first

2. 2

   Using a multimeter, measure the resistance between terminal 1 and terminal 2 of the high-range and medium-range clutch solenoids (should read between 8 and 11 Ohms)

3. 3

   Check the rotary position sensor (potentiometer) for the synchronizer to ensure the signal is not out of range, which indicates a wiring harness short/open, a damaged potentiometer, or a mechanical bind

1. 1

   Electrical Component Replacement

   If the resistance of the high or medium range clutch solenoid is not between 8 - 11 Ohms, remove and replace the faulty clutch solenoid.

2. 2

   Potentiometer Replacement

   If the solenoid tests fine but the synchronizer position signal is out of range or erratic, inspect the wiring harness. If the wiring is intact, remove and replace the synchronizer potentiometer.

3. 3

   Transmission Calibration

   After replacing any transmission electrical components (solenoid or potentiometer), you must perform the transmission calibration procedure. Put the software in calibration mode and run the routine so the TCU can relearn the engagement and disengagement points of the synchronizers.

4. 4

   Mechanical Inspection

   If the electrical components test fine and calibration fails, the issue is a mechanical problem on the driveline. The transmission will need to be split to inspect the mechanical synchronizer assembly, shift forks, and clutch packs for physical wear, binding, or failure.