The torque converter on an automatic transmission is similar to the clutch on a vehicle with a manual transmission. The torque converter is the part that is responsible for the vehicle shifting smoothly between gears. If your torque converter is not working properly, your vehicle may appear to have transmission problems because it may not be shifting through the gears correctly or at all. You can perform a stall test on the vehicle at home to help you determine if the torque converter is the problem.
Things You'll Need
Get in your vehicle and drive it to a flat, level location. Allow the vehicle to warm up, so the engine and transmission are at their normal operating temperatures.
Put the vehicle in gear and release the brake. Do not touch the accelerator. If the vehicle does not begin moving slowly forward on its own, there is a good chance your problem is the torque converter.
Place one foot on the brake and one foot on the accelerator. Pay attention to the tachometer as you increase pressure on the accelerator without allowing the vehicle to move forward; make note of the maximum rpm the vehicle reaches without moving. This is called a stall test.
Get out your vehicle's owner's manual and compare the results of your stall test to the manufacturer's specifications for a stall test. If the maximum rpm you reached is similar to what the manufacturer says the vehicle should achieve, your torque converter is fine. If your maximum rpm is significantly different from manufacturer's guidelines, take your vehicle to a mechanic to have the torque converter formally diagnosed and repaired.
Tips & Warnings
- Do not perform a stall test for more than five seconds at a time. Performing a stall test on a vehicle that is already damaged may further damage vehicles. Do not attempt a stall test on a vehicle with an anti-lock braking system as it may cause problems with the electronic monitoring sensors.
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