Overdrive Unit Parts

Install 4th clutch outer and inner seals on center support with lips facing down, apply petroleum jelly to seals. Install 4th clutch piston into case, aligning piston tab with wide case spline. Position return spring and retainer assembly on piston. Compress retainer assembly and install support-to-4th clutch spring snap ring.
NOTE: The 4th clutch inner seal, installed on center support, is identified by a White stripe.
Install internal gear-to-support thrust washer into case with tangs down. Install overdrive internal gear, hub end first, on forward clutch shaft. Install overdrive carrier-to-sun gear thrust bearing assembly into overdrive internal gear with large diameter race against carrier.

Grasp turbine shaft and lower overrun clutch and overdrive carrier assembly into case and rotate into position. Select proper 4th clutch plates. See FOURTH CLUTCH PLATE USAGE . Oil and install 4th clutch plates into case. See Fig 1 . Install clutch pack retaining snap ring. Install oil deflector plate into case with tangs facing up.

CAUTION: Note installation order of 4th clutch plates. The center has 2 steel plates together and thick plate is on top. Incorrect installation sequence will cause damage.

Fig 1: 4th Clutch Plate Installation Sequence

Courtesy of GENERAL MOTORS CORP.

FOURTH CLUTCH PLATE USAGE

Application	Steel	Composition
All Models	3	2

Install a new pump-to-case gasket on pump and retain with petroleum jelly. Install 2 alignment pins into pump attaching bolt holes opposite each other. Install pump assembly in case. Install pump attaching bolts with NEW washers. Remove alignment pins and install remaining bolts and washers. Tighten oil pump attaching bolts.

NOTE: At this point, recheck overdrive unit end play to verify that correct overdrive end play thrust washer has been installed. See Overdrive End Play.