GM Service Manual Online
For 1990-2009 cars only

Warning: When the transmission is at operating temperatures, take necessary precautions when removing the check/fill plug, to avoid being burned by draining fluid.

  1. Remove the drainage plug and drain the AT fluid while the engine is stopped.
  2. Note: The fluid can not be drained completely.

  3. Replace the drainage plug and tighten to 44 N·m (22 lb ft)
  4. Note: 

       • Do not mix different kinds of oil.
       • Using a different type of ATF may cause problems with the clutch and brake.

  5. Replace the same quantity of specified fluid as was drained from the filler tube.
  6. Specified AT fluid: ESSO JWS3314

    Reference: Total quantity of Fluid 4.78L (5.05 qt)

    Note: 

       • Do not mix different kinds of oil.
       • Using a different type of ATF may cause problems with the clutch and brake.

  7. Start the engine and allow it to idle for at least five minutes.
  8. Danger: To avoid any vehicle damage, serious personal injury or death when major components are removed from the vehicle and the vehicle is supported by a hoist, support the vehicle with jack stands at the opposite end from which the components are being removed and strap the vehicle to the hoist.

    Caution: Support the lower control arms in the normal horizontal position in order to avoid damage to the drive axles. Do not operate the vehicle in gear with the wheels hanging down at full travel.

  9. Lift up the vehicle. Drive the engine gradually until the engine speed reaches approximately 50 km/h (30 mph) in the "D" range; then depress the brake pedal to allow the engine to idle. Release the brake for about 10 seconds in the "R" range, and depress the brake again to allow the engine to idle. Repeat this sequence of steps 2 or 3 times.
  10. Note: The fluid level check must be carried out while the engine idles after the transmission has warmed up.

  11. Now check the AT fluid level.