GM Service Manual Online
For 1990-2009 cars only

Note:  Perform the test at the ATF (Automatic Transmission Fluid) temperature 50-80°C (122-176°F) in the normal operation.

D Position Test

Shift into the D position and fully depress the accelerator pedal and check the following points.

  1. Check the up-shift operation.
  2. Check that 1-2, 2-3 and 3-4 up-shifts take place.

    4th Gear Up-shift Prohibition Control

    • Engine coolant temperature is 40°C (104°F) or less and vehicle speed is at 70 km/h (43 mph) or less.
    • ATF temperature is 0°C (32°F) or less.

    4th Gear Lock-up Prohibition Control

    • Brake pedal is depressed.
    • Accelerator pedal is released.
    • Engine coolant temperature is 60°C (140°F) or less.
    • ATF temperature is 10°C (50°F) or less.
  3. Check for shift shock and slip.
  4. Check for shock and slip at the 1-2, 2-3 and 3-4 up-shifts.

  5. Check for abnormal noise and vibration.
  6. Check for abnormal noise and vibration when up-shifting from 1-2, 2-3 and 3-4 while driving with the shift lever in the D position, and check while driving in the lock-up condition.

    The check for the cause of abnormal noise and vibration must be done thoroughly as it could also be due to loss of balance in the differential, torque converter clutch, etc.

  7. Check abnormal shock and slip at kick-down.
  8. Check the lock-up mechanism.
  9. • Drive in D position (4th gear), at a steady speed (lock-up ON).
    • Lightly depress the accelerator pedal and check that the engine speed does not change abruptly.
      If there is a big jump in engine speed, there is no lock-up.

3 Position Test

Shift into the 3 position and fully depress the accelerator pedal and check the following points.

  1. Check the up-shift operation.
  2. There is no 4th up-shift in the 3 position.

  3. Check the engine braking.
  4. While running in the 3 position and 3rd gear, release the accelerator pedal and check the engine braking effect.

  5. Check for abnormal noise during acceleration and deceleration, and for shock at up-shift and down-shift.

2 Position Test

Shift into the 2 position and fully depress the accelerator pedal and check the following points.

  1. Check the up-shift operation.
  2. There is no 3rd up-shift and lock-up in the 2 position.

  3. Check the engine braking.
  4. While running in the 2 position and 2nd gear, release the accelerator pedal and check the engine braking effect.

  5. Check for abnormal noise during acceleration and deceleration, and for shock at up-shift and down-shift.

L Position Test

Shift into the L position and fully depress the accelerator pedal and check the following points.

  1. Check the no up-shift.
  2. While running in the L position, check that there is no up-shift to 2nd gear.

    There is no lock-up in the L position.

  3. Check the engine braking.
  4. While running in the L position, release the accelerator pedal and check the engine braking effect.

  5. Check for abnormal noise during acceleration and deceleration.

R Position Test

Note: Before conducting this test ensure that the test area is free from people and obstruction.

Shift into the R position, lightly depress the accelerator pedal, and check that the vehicle moves backward without any abnormal noise or vibration.

P Position Test

Stop the vehicle on the grade (more than 5 degrees) and after shifting into the P position, release the parking brake. Then, check that the parking lock pawl holds the vehicle in place.