GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2009 🢒 Cobalt 🢒 Transmission 🢒 Automatic Transmission - 4T45-E 🢒 Intermediate/Fourth Servo Assembly Replacement

Removal Procedure
  1. Raise the vehicle. Refer to Lifting and Jacking the Vehicle.
  2. Remove the oil pan and filter. Refer to Automatic Transmission Fluid Filter and Seal Replacement.

    3. Object Number: 589165 Size: SH
  3. Remove the two intermediate/4th servo cover bolts, the servo and the spring.

Disassemble Procedure

    Object Number: 1778405 Size: SH
  1. Remove the piston and pin assembly (76 and 77) from the servo cover (80).
  2. Remove the snap ring (70) from the servo pin (76).
  3. Remove the piston (77) and the servo cushion springs (68) from the servo pin (76).
  4. Remove the servo piston seals (78, 79) from the servo cover (80).
  5. Discard the servo piston seals (78 and 79). Do not reuse the servo piston seals.

    6. Object Number: 1778408 Size: SH
  6. Inspect all components (70, 77-80) for damage.
  7. Inspect the fluid feed holes for proper opening.
  8. Inspect the bolt hole threads for debris and stripping.
  9. Inspect the seal grooves for damage.
  10. Clean and dry each component.

Assemble Procedure

    Object Number: 1778405 Size: SH
  1. Install the servo cushion springs (68) and the servo piston (77) onto the servo pin (76).
  2. Install the snap ring (70) onto the servo pin (76) in order to retain the springs (68) and piston (77).
  3. Install the new seals (78 and 79) onto the servo piston (77) and the servo cover (80).
  4. Install the servo piston assembly into the servo cover (80). Lubricate the piston seals with transmission fluid in order to aid in assembly.

Installation Procedure

    Caution: Refer to Fastener Caution in the Preface section.


    Object Number: 589165 Size: SH
  1. Install the intermediate/4th band servo piston spring, the servo and the servo cover bolts.

    2. Tighten the bolts to 12 N·m (106 lb in).

  2. Install the filter and the pan. Refer to Automatic Transmission Fluid Filter and Seal Replacement.
  3. Lower the vehicle.
  4. Fill the transmission with DEXRON® VI fluid.
  5. Inspect the transmission oil level. Refer to Transmission Fluid Check.

    6. Note: 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 engine control module (ECM), powertrain control module (PCM) or transmission control module (TCM) will need to relearn TAP values. Transmission performance may be affected as new TAP values are learned.

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