GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Buick 🢒 2009 🢒 Lucerne 🢒 Transmission 🢒 Automatic Transmission - 4T80-E 🢒 Fourth Servo Overhaul

    Object Number: 15524 Size: SH
  1. Remove the following parts:
    2. • The 4th servo piston seals (532, 525)
    • The snap ring (531)
    • The apply pin (527)
    • The spring and retainer assembly (533)

    Object Number: 15525 Size: SH
  2. Inspect the following parts:
    3. • The 4th servo piston (529) for cracks
    • The apply pin (527) for damage
    • The spring and retainer assembly (533) for damage
    • The servo cover (524) for damage

    Object Number: 15526 Size: SH
  3. Install the following parts:
    4. • The new piston seal (532) onto the 4th servo piston (529)
    • The apply pin (527)
    • The spring retainer (533) into the 4th servo piston (529)
    • Attach the snap ring (531) to the apply pin (527).

    Object Number: 11837 Size: SH
  4. Install the 4th servo piston assembly (529) and the spring (533) into the 4th servo cover (524).

    5. Apply pipe thread sealant GM P/N 12346004 to bolt threads before installation.

  5. Install the 4th servo piston and cover assembly into the case.

    6. Caution: Refer to Fastener Caution in the Preface section.


    Object Number: 15541 Size: SH
  6. Install the 4th servo cover bolts into the case. Hand tighten the bolts while holding the piston compressed, then tighten in a star pattern to 8-14 N·m (6-10 lb ft).