GM Service Manual Online
For 1990-2009 cars only

Tools Required

J 21867 Pressure Gauge

Notice: The total test running time should not be longer than 2 minutes. Running the test longer than 2 minutes may damage the transaxle.

Caution: Keep the brakes applied at all times in order to prevent unexpected vehicle motion. Personal injury may result if the vehicle moves unexpectedly.

  1. Check the fluid. Refer to Transmission Fluid Check .
  2. Check and adjust the Throttle Valve (TV) cable and manual linkage.
  3. Remove the line pressure plug and install J 21867 .
  4. Start the engine, set the parking brake, and raise the engine speed to 1,000 RPM.
  5. Check transmission line pressure:
  6. • Minimum Line Pressure -- no changes to normal TV cable travel.
    • Full Line Pressure -- hold the TV cable to full travel.
    • Note the pressure readings in all of the gear ranges for Minimum and Full Line Pressure. Compare them with information in the table below.
  7. Refer to Symptoms - Automatic Transmission in order to diagnose the line pressure readings that are either too high or too low.