GM Service Manual Online
For 1990-2009 cars only

Special Tools

    • KM580 Transmission Line Pressure Adapter
    • SA9127E Gage Bar Set

For equivalent regional tools, refer to Special Tools.


    Object Number: 1998894  Size: SH
  1. Raise and support the vehicle. Refer to Lifting and Jacking the Vehicle.
  2. Remove the left front splash shield. Refer to Front Fender Liner Replacement.
  3. Remove the retaining clips for the transmission and cooler lines.
  4. Remove the cooler lines from the transmission.

  5. Object Number: 1998895  Size: SH
  6. Remove the automatic transmission fluid pressure test hole plug (816) with the O-Ring seal (815).

  7. Object Number: 1998896  Size: SH
  8. Install the KM580 line pressure adapter  (1) with sealing washer into the fluid test hole plug.
  9. Connect the KM580 line pressure adapter  (1) to the SA9127E gage bar set  (2).
  10. Install the oil cooler lines and retainer clips.
  11. Fully apply the parking brake.
  12. Connect a scan tool for engine RPMs.
  13. Start the engine and allow the engine to warm up at idle.
  14. Firmly apply the brake and shift into REVERSE (R).
  15. Allow the engine to idle and record the line pressure. Line pressure should be 510-610 kPa (74-89 psi).
  16. Note: Do not perform the 2545 RPM test longer than 5 seconds.

  17. Increase the engine speed to 2545 RPM and record the line pressure. Line pressure should be 1470-1690 kPa (213-245 psi).
  18. Allow the transmission fluid to cool at idle in PARK (P) for at least one minute.
  19. Firmly apply the brake and shift into DRIVE (D).
  20. Allow the engine to idle and record the line pressure. Line pressure should be 360-420 kPa (52-56 psi).
  21. Note: Do not perform the 2600 RPM test longer than 5 seconds.

  22. Increase the engine speed to 2545 RPM and record the line pressure. Line pressure should be 1100-1280 kPa (160-186 psi).
  23. If the line pressure reading is not within specifications refer to the Line Test Results table.
  24. Caution: Refer to Fastener Caution in the Preface section.


    Object Number: 1998895  Size: SH
  25. Remove the tools and install the automatic transmission fluid pressure test hole plug (816) and a new O-Ring (815). Tighten the test hole plug to 7 N·m (62 lb in).
  26. Install the transmission oil cooler lines.
  27. Install the left front splash shield. Refer to Front Fender Liner Replacement.

Line Test Results

Result

Possible Cause

Higher than standards in both Drive and Reverse

    • Line pressure control solenoid - (STH) (316) failure
    • Primary regulator valve (379) failure

Lower than standards both Drive and Reverse

    • Line pressure control solenoid  - (STH) (316) failure
    • Primary regulator valve  (379) failure
    • Fluid pump (2) failure

Lower than standards only Drive

    • Drive hydraulic circuit failure
    • Forward Clutch (18) failure

Lower than standards only Reverse

    • Reverse hydraulic circuit failure
    • Reverse gear clutch (23) failure