GM Service Manual Online
For 1990-2009 cars only

Important: 

   • Do not hold the stall condition for longer than 5 seconds at a time.
   • Be sure to cool the transmission, idling for at least 30 seconds before starting the next test.

  1. Check the automatic transmission/transaxle fluid level and condition. Refer to Transmission Fluid Check.
  2. Block the front and rear wheels and apply the parking brake fully.
  3. Attach an engine tachometer.
  4. Warning: Keep the brakes applied at all times in order to prevent unexpected vehicle motion. Personal injury may result if the vehicle moves unexpectedly.

  5. Start the engine. Move the select lever to "D" and depress the accelerator pedal while monitoring the engine speed. Quickly read the engine speed (stall speed) at the point that the engine speed becomes constant (stall point).
  6. Carry out this test in "D" and "L" also.

Stall speed (RPM): 2850

Result

Probable Cause

Lower than the specified level in all ranges

    • Insufficient engine output
    • Faulty torque converter

Higher than the specified level in "D" and "2"

    • One-way clutch slip
    • Low clutch slip

Higher than the specified level in "D', "2", and "L"

Low clutch slip

Higher than the specified level in "R"

    • Reverse clutch slip
    • Low and reverse brake slip

Higher than the specified level in "R" and "L"

Low and reverse brake slip

Higher than the specified level in all ranges

    • Low line pressure
    • Faulty oil pump
    • Faulty pressure regulator