Overdrive Does Not Engage
- Insufficient oil level in the unit
- Solenoid not operating due to electrical system fault
- Solenoid operating lever out of adjustment
- Insufficient hydraulic pressure due to improper seating of the pump non-return valve (usually caused by dirt on the ball seat)
- Pump not working
- Filter blocked
- Inadequate hydraulic pressure due to sticking or worn relief valve
- Damaged internal parts requiring removal and overhaul of the unit
Overdrive Falls Out of Operation
- Inadequate oil pressure
- Incorrect adjustment
- Solenoid weak
- Open circuit in isolator switch
- Accumulator piston damage
- Defective relay
- Throttle switch is incorrectly adjusted
- Incorrect solenoid wiring
- Open circuit in relay winding
Overdrive Does Not Release – Do not engage reverse gear since damage may result
- Fault in the electrical control system
- Blocked restrictor jet in operating valve
- Solenoid operating lever out of adjustment
- Sticking cone clutch
- Damaged internal parts requiring removal and overhaul of the unit
Clutch Slip in Overdrive
- Insufficient oil level in the unit
- Solenoid operating level out of adjustment
- Insufficient hydraulic pressure due to improper seating of the pump non-return valve (usually caused by dirt on the ball seat)
- Filter blocked
- Inadequate hydraulic pressure due to sticking or worn relief valve
Clutch Slip in Reverse or Free-Wheel Condition on Overrun
- Solenoid operating lever out of adjustment
- Partially blocked restrictor jet in operating valve
- Worn clutch linings
Overdrive Engage Slowly
- Low oil pressure
- Accumulator piston damaged
Overdrive Does Not Engage Until Warm
- Incorrect oil
Noisy Operation
- Rear overdrive bearing is worn
- Annulus gears worn
Vehicle Will Not Back Up
- Overdrive stuck
- Restrictor hole plugged
- Magnet and filter screen missing