Overdrive Servo Assembly
Overdrive Servo Assembly
Refer to Fig. 25.
Removal
1. Raise the vehicle on a hoist so the transmission fluid pan is accessible.
2. Starting at the rear and working toward the front, loosen the oil pan attaching bolts and drain the fluid from the transmission. If the same fluid is to be used again, filter the fluid through a 100 mesh screen. Reuse the fluid only if the fluid is in good condition.
3. Remove the transmission fluid pan attaching bolts, pan and gasket. Discard gasket.
4. Remove three dacron filter to valve body attaching bolts and remove the dacron filter, grommet and gasket. Discard gasket. If the fluid is contaminated, discard the dacron filter. (Do not clean the filter).
5. Remove the detent spring and attaching bolt.
6. Remove the valve body to case attaching bolts (25). Remove the valve body. Discard valve body to case gasket.
7. Depress overdrive servo piston cover with a hammer handle and remove the retaining snap ring.
8. using Tool T8OL-77030-B or equivalent, 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.
9. 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.
6. Install the overdrive piston, cover and spring into the overdrive servo pocket in the case. Make sure the servo rod contacts the band apply pocket while installing. Failure to do so will result in a no 3-4 shift condition.
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. 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.
9, Remove nicks and burrs with a "fine honing stone" and clean the expected areas thoroughly. Failure to do so may cause improper seating of the valve body separator plate to the hydraulic passages in the case, and subsequent cross leakage.
10. Clean and inspect the valve body, prior to installation.
11. Position a new separator plate gasket to the separator plate.
12. Using valve body guide Pins, T8OL-77100-A or equivalent, position the valve body to the case, making sure that the inner manual lever and inner TV lever are engaged.
13. Install and tighten the attaching bolts (25) to 9-14 N.m (80-120 in-lbs).
14. Install the detent spring and attaching bolt.
15. Remove the guide Pins T8OL-77100-A or equivalent and install and tighten the remaining two valve body-to-case bolts.
16. Position the throttle lever spring against the separator plate.
17. Using three dacron filter attaching bolts, install the dacron filter and gasket to the valve body and tighten attaching bolts to 9-14 N.m (80-120 in-lbs).
18. Glean the transmission oil pan and gasket surfaces thoroughly.
19. Using a new oil pan gasket, secure the pan to the transmission case. Tighten the attaching bolts to 8.0-13.5 N.m (6-10 ft-lbs).
20. Lower the vehicle and fill the transmission to the Correct level with the specified fluid. Fluid - A/T
21. Adjust TV cable linkage. Adjustments