How to troubleshoot your transmission jack

How to troubleshoot your transmission jack

Transmission jacks are powerful, multitask lifting systems that are essential in most repair shops. But like any equipment, they are most effective when properly maintained, regularly inspected for damage and used correctly.

Even the best-maintained transmission jacks occasionally give mechanics trouble. Knowing the potential issues and troubleshooting steps can minimize downtime and get your technicians 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.

This Tech Tip was contributed by BendPak.

You May Also Like

U-POL Raptor rubberized undercoating

Kevin Lewis of U-POL shows how to apply Raptor Rubberized Undercoating, a product that protects against rust and stone chips.


In this video, Jason Stahl and Kevin Lewis, regional sales manager with U-POL, discuss U-POL’s Raptor Rubberized Undercoating, a product that protects vehicle underbodies, quarter panels and wheel wells against rust and stone chips. Watch the video above to see.

Rislone releases DEF Crystal Clean

The company says this product scrubs away crystal contaminants from the selective catalytic reduction (SCR) systems of diesel vehicles

Dobbs Leasing named PacLease N.A. Franchise of the Year

In 2023, Dobbs Leasing achieved a 71% year-over-year increase in total vehicles in-serviced with PacLease, while adding three new locations.

Florida Pneumatic releases new Aircat riveters

Two models with two different levels of power have been released.

HDA Truck Pride member Southside Trailer Service acquires PBS Brake & Supply

The acquisition unites 105+ collective years of experience and highlights collaborative spirit within HDA Truck Pride’s network.


Other Posts

Using AI to capture tire data, control costs and reduce downtime

Good fleet management is vital for any trucking company, but the days of searching for important information in stacks of notebooks are over.

BAE Systems, Eaton test electric commercial truck drive technology

Testing occurred at Eaton’s proving grounds in Marshall, Mich., on a Class 7 demonstration vehicle.

International Truck integrates S13 engine with Allison automatic transmissions

Allison 3414 Regional Haul Series, 4000 Series fully automatic transmissions available for International RH, HX Series trucks, respectively.

Embracing truck service changes that come with EVs

Young Trucks adapts to EVs with Volvo’s certification program, investing in equipment, training, and safety for heavy-duty electric truck service.