With 4R44E/4R55E

TORQUE CONVERTER CLUTCH TEST

NOTE: Engine coolant temperature must be above 128° and below 240° F. This temperature can be obtained after approximately 15 minutes of highway driving. Since most converter clutch shifts are difficult to feel, a tachometer and/or vacuum gauge must be connected to engine.

1. Drive vehicle at approximately 50 mph and, while maintaining this speed, tap the brake pedal with the left foot.
2. The engine RPM and should increase when the throttle is released and decrease in about five seconds (converter engagement) after throttle is reapplied. If this does not occur, refer to Torque Converter Operation Concerns on the diagnosis by symptom index. 4R44E/4R55E