Case IH 72 – Transmission ECM: SYNC_POPPED_OUT_ERR

The Forward/Reverse (F/R) Synchronizer has disengaged from its position. The transmission gears are currently disabled due to this fault, but the fault display can be cleared or reset by using the Clutch Pedal (CP) or the Shuttle Lever (SL).

• JXC
• Case IH JX
• Case IH JXU
• Case IH Farmall

1. 1

   Inspect the external shift levers and relay rods for incorrect adjustment, which is a primary cause of spontaneous gearbox disengagement

2. 2

   Check all rod pivots for stiffness or partial seizure

3. 3

   Verify the F/R Synchronizer Position Sensors and the F/R Synchronizer Solenoids (including the dump solenoid circuit) to ensure the ECM can accurately verify the synchronizer's position

1. 1

   Adjust Linkages

   Adjust the external levers and relay rods to their correct OEM specifications.

2. 2

   Lubricate

   Lubricate any stiff rod pivots and test the tractor to see if the spontaneous disengagement stops.

3. 3

   Prepare for Split

   If the gearbox continues to pop out of gear, the internal components are worn or lifted. Lock the front wheels using chocks, remove the top link of the third point, and proceed to split the tractor to remove the transmission/gearbox.

4. 4

   Disassemble Gearbox

   Remove the gearbox shafts and guards to access the internal synchronizer assemblies.

5. 5

   Inspect Internal Components

   Inspect the Shuttle control synchronizer (F/R synchronizer), the selector sleeves (for high/low or medium speeds), and the shift forks for excessive wear, damaged teeth, or weak detent springs.

6. 6

   Replace Parts

   Replace the worn synchronizer rings, detent balls, and springs.

7. 7

   Reassemble

   Reassemble the gearbox. Apply sealing compound to specific mating surfaces on the gearbox rear cover and casing during reassembly. Reinstall the transmission and recalibrate the ECM if necessary.