Overdrive Servo Assembly

Tools Required:

• Servo Piston Remover T80L-77030-B

Removal

NOTE: Some vehicles may require the removal of interfering exhaust system components.

1. Raise vehicle on a hoist so the transmission oil pan is accessible. Refer to Section 00-02.

2. Starting at the rear and working toward the front, loosen the oil pan retaining bolts and drain the fluid from the transmission. It may be necessary to use a 3/8-inch or 1/4-inch drive ratchet with a 10mm universal socket to remove oil pan bolts.

3. Remove the transmission oil pan retaining bolts, pan and gasket. Discard gasket.

4. Remove three filter-to-valve body retaining bolts and remove the filter, grommet and gasket. Discard gasket. If the fluid is contaminated, refer to Transmission Fluid Condition Check procedure under Diagnosis and Testing.

5. Remove the detent spring and retaining bolt.

6. Remove the valve body-to-case retaining bolts. Remove the valve body. Discard valve body-to-case gasket.

7. Retain band against drum using a small flat object or screwdriver to prevent band movement during servo removal.

8. Depress overdrive servo piston cover with a hammer handle and remove the retaining snap ring.

9. Using Servo Piston Remover T80L-77030-B, apply air pressure to the servo piston release passage in order to remove the overdrive servo piston cover and spring. Remove the piston from the cover.

10. Remove the rubber seals from the piston and the cover.

Installation

1. Clean and inspect the servo piston and cover for nicks and/or burrs. Clean and inspect the servo piston pocket in the case for nicks and burrs also.

2. Install new servo piston and cover seals on the piston and cover, respectively.

3. Lubricate the piston seals with either clean transmission fluid or a petroleum jelly.

4. Install the servo piston into the cover, lubricate the cover seals and the overdrive servo pocket in the case.

5. Assemble the return spring to the servo piston.

    CAUTION: Make sure the servo rod contacts the overdrive band apply pocket. Failure to do so will result in a no 3-4 shift condition.

6. Install the overdrive piston cover and spring into the overdrive servo pocket in the case.

7. Using the handle of a hammer, depress the overdrive servo sufficiently to gain clear access to the retaining snap ring groove in the case. Install the snap ring.

8. Remove tool used to retain band.

9. Inspect the outer edge of the overdrive servo pocket for possible nicks and burrs which might have been raised during the removal or installation of the retaining snap ring.

    CAUTION: Failure to remove nicks and burrs may cause improper seating of the valve body separator plate to the hydraulic passages in the case and subsequent cross leakage.

10. Remove nicks and burrs with a fine honing stone and clean the affected areas thoroughly.

11. Clean and inspect the valve body as outlined in this Section.

12. Position a new separator plate gasket to the separator plate.

13. Position the valve body to the case, making sure that the inner manual lever and inner TV lever are engaged.

14. Install two shoulder bolts.

15. Install valve body-to-case retaining bolts. Tighten to 9-11 Nm (80-97 lb-in).

16. Install the detent spring and retaining bolt.

17. Tighten the two shoulder bolts to 9-11 Nm (80-97 lb-in).

18. Position the TV lever torsion spring against the separator plate.

19. Using three filter retaining bolts, install the filter and gasket to the valve body. Tighten retaining bolts to 9-14 Nm (80-123 lb-in).

20. Clean the transmission oil pan and gasket surfaces thoroughly.

21. Using a new oil pan gasket, secure the pan to the transmission case. Tighten the retaining bolts to 8-13.5 Nm (71-119 lb-in).

22. Install any exhaust system components that were removed.

23. Lower the vehicle and fill the transmission to the correct level with Synthetic MERCON® Multi-Purpose Automatic Transmission Fluid E6AZ-19582-B (ESR-M2C163-A2) or equivalent. Start the engine and shift the transmission to all ranges, then recheck the fluid level. Refer to the Transmission Fluid Level Check procedure under Diagnosis and Testing.

24. Adjust TV linkage cable system as outlined under Linkage Adjustment.