Torque Converter Stall Test
If the torque converter stators one way clutch is suspected of slipping or being seized a torque converter stall test should be performed before bench testing the converter. Always check with vehicle manufacturer before performing this test.
To perform this test install a tachometer, chock all four wheels, and set the parking brake. Make sure the tachometer is viewable from the drivers seat. Place your foot firmly on the brake pedal and place the transmissions shift selector in Drive. While holding the brake pedal press and hold the throttle pedal to the floor for 2 or 3 seconds. Always check with the manufacturers recommendations because this test places stress on the transmission. Never exceed 5 seconds. Compare the reading (stall speed) on the tachometer to the manufacturers specifications.
During a stall test the torque converters impeller is spinning at maximum speed while the turbine is being held stationary. Since everything from the turbine back is being held stationary a vibration like an out of balance drive shaft would not appear during a stall test.
Troubleshooting the Stall Test:
If this reading is below specifications the torque converters stator one way clutch is spinning freely or there is a restriction in the exhaust system. If the reading is above specifications the transmissions clutches and bands are slipping.
