GM Service Manual Online
For 1990-2009 cars only

Removal Procedure


    Object Number: 687542  Size: SH
  1. Remove the transmission filter. Refer to Automatic Transmission Fluid and Filter Replacement .
  2. Compress the reverse boost valve sleeve into the bore of the oil pump to release tension on the reverse boost valve retaining ring.
  3. Remove the reverse boost valve retaining ring, then slowly release tension on the reverse boost valve sleeve.

  4. Object Number: 298157  Size: SH
  5. Remove the reverse boost valve sleeve (5) and the reverse boost valve (4).
  6. Remove the pressure regulator isolator spring (3) and the pressure regulator valve spring (2).
  7. Remove the pressure regulator valve (1).

Installation Procedure


    Object Number: 298157  Size: SH
  1. Install the pressure regulator valve (1).
  2. Install the pressure regulator isolator spring (3) and the pressure regulator valve spring (2).
  3. Install the reverse boost valve (4) in the reverse boost valve sleeve (5).
  4. Install the reverse boost valve (4) and sleeve (5) in the oil pump cover.

  5. Object Number: 687542  Size: SH
  6. Compress the reverse boost valve sleeve into the bore of the oil pump to expose the retaining ring slot.
  7. Install the reverse boost valve retaining ring, then slowly release tension on the reverse boost valve sleeve.
  8. Install the transmission filter. Refer to Automatic Transmission Fluid and Filter Replacement .
  9. Important: It is recommended that transmission adaptive pressure (TAP) information be reset.

    Resetting the TAP values using a scan tool will erase all learned values in all cells. As a result, The ECM, PCM or TCM will need to relearn TAP values. Transmission performance may be affected as new TAP values are learned.

  10. Reset the TAP values. Refer to Transmission Adaptive Functions .