Even the best-maintained transmission jacks occasionally give mechanics trouble. Knowing the potential issues and troubleshooting steps can minimize downtime and get you back to work quickly.
Many transmission jack issues are caused by low hydraulic fluid levels. If you have any of the following problems, start by checking the fluid level and topping off as needed:
- Unit fails to extend or only partially extends.
- Incomplete or spongy cylinder response when foot pedal is pumped.
- Abnormal leakage through unit breather.
Note that air in the system can also cause a spongy cylinder response. Air can accumulate within the hydraulic system during shipment or after prolonged use. If the fluid level is correct, you may need to bleed the hydraulic system. Check your owner’s manual for the steps to follow. For Ranger products, pump the jack to the highest point where the first and second piston rams are both at maximum height. Get someone else to help you keep the release pedal pressed while you activate the foot pedal about 20 times. Then let go of the release pedal.
Contamination of the hydraulic system can cause the cylinder to fail to extend or to retract when the foot pedal is released. If this occurs, disassemble the jack and clean it. Remember to only use hydraulic jack oil. Do not use hydraulic brake fluid.
If the jack won’t extend when the foot pedal is pumped or it retracts on its own, the fluid is clean and adequate, flush the release valve by pumping the foot pedal with the valve open. There could also be a cylinder packing failure — this can be remedied by installing a new seal kit.
User error is also a common issue. If your cylinder is creeping when holding a load or won’t retract when the release pedal is activated, you may be trying to lift a load that is too heavy or too light for the equipment rating.