Automatic Transaxle Overhaul & Testing - 4T80-E: Overhaul Oldsmobile Aurora II

FINAL DRIVE CARRIER ASSEMBLY & END PLAY CHECK

1. Use Dial Indicator Post (J-25025-7A) and Dial Indicator (J-8001-3) to check end play. Pry up on speed sensor rotor through vehicle speed sensor hole. End play should be.006-.026" (.15-.65 mm). (Scheme 3) Record this measurement for reassembly.
2. Remove case extension, thrust washer, bearing and seal. Remove scavenge tube and seal from transaxle case. Lock parking gear with park actuator. Remove 4 differential bolts and differential carrier.
3. Push on output shaft and remove snap ring. Remove left-side differential gear and remove output shaft from front end of transaxle. Remove final drive carrier, thrust bearing, final drive sun gear and internal gear.

Scheme 3

LOWER TRANSAXLE ASSEMBLY

Remove lower oil pan and oil scavenge screens. Disconnect manual valve link and wiring harness connectors. Remove oil transfer plate. Leave specified bolts in assembly to hold lower control valve and accumulator assembly together. (Scheme 4) Remove control valve and accumulator cover assembly.

Scheme 4

CLUTCH & BAND ASSEMBLIES

1. Remove 2nd clutch plate assembly. (Scheme 12) Remove reverse clutch support thrust washer. Remove reverse clutch housing and 2nd sprag assembly. (Scheme 10) Remove 4th band. Holding 3rd clutch housing by input shaft, remove 3rd clutch and reaction carrier assemblies. (Scheme 7) Remove reaction carrier shell. (Scheme 30)
2. Move manual control shaft from "P" position. Remove parking pawl, spring and pivot pin assembly. Remove 2 forward and coast clutch support bolts from transaxle case. (Scheme 5) Remove oil cooler return fitting from forward and coast clutch support.
3. Using Forward/Coast Clutch Puller (J-39053), remove clutch assemblies. (Scheme 5) Remove low-reverse band and support fretting ring. (Scheme 15)
4. Remove detent spring. Remove detent lever pivot arm. While holding detent lever in place, remove manual shaft nut. Remove detent lever and actuator rod. Remove manual shaft assembly and case seals. (Scheme 6)

Scheme 5

Scheme 6

Reassembly

1. Lubricate seal rings. Using seal ring expander, install both seal rings (if removed). Using Seal Ring Sizer (J-34741-3), compress seal rings and leave tool in place until input housing is installed.
2. Apply petroleum jelly to 3rd clutch piston seals. While rotating, insert piston into 3rd clutch housing. Install spring and retainer assembly. Place retainer on top of spring and retainer assembly. Using appropriate compressor, compress spring and retainer assembly and install snap ring.
3. Install apply plate. Install 4 friction plates and 3 steel plates, beginning with friction and alternating with steel plate. (Scheme 7) Install backing plate with stepped side up. Install snap ring, thrust washer and 3rd clutch hub assembly.
4. Install thrust bearing with rolled inner lip facing clutches. Install reaction sun gear and shell assembly. Install thrust bearing inside reaction carrier, and install reaction carrier assembly.
5. Install reaction carrier thrust bearing with Black side facing reaction carrier. Install input sun gear and snap ring. Using petroleum jelly, attach selective thrust washer and thrust bearing to top of clutch housing. Install 3rd clutch and reaction carrier in driven sprocket support. Apply 50-60 psi (3.5-4.2 kg/cm 2 ) to appropriate passage to ensure proper operation of 3rd clutch. (Scheme 9)

Scheme 7

Scheme 8

Scheme 9

1. Install NEW seals on reverse clutch piston. Apply petroleum jelly to seals, and install clutch piston into housing. Install spring and retainer assembly. Install retainer seat. Using appropriate compressor, install snap ring.
2. Install Belleville plate. Install 2 steel plates and 2 friction plates, beginning with steel plate and alternating with friction plate. Install apply plate with stepped side up. Install snap ring. Install 2nd clutch outer race thrust washer.
3. Install sprag clutch into outer race. Ensure 2nd sprag rotates in correct direction. With sprag assembled on top of reverse clutch and race housing, hold housing and ensure 2nd sprag race turns clockwise. (Scheme 11) Install sprag clutch retainer. Install NEW 2nd sprag spiral snap ring, if removed. Ensure spiral snap ring tabs lock into place and is fully seated.

Scheme 10

Scheme 11

Apply petroleum jelly to piston seals. While rotating, insert piston into driven sprocket support. Install spring and retainer assembly. Compress spring assembly, and install snap ring. Install backing plate with flat side up. Install 4 friction plates and 4 steel plates, beginning with a friction plate and alternating with steel plates. Install apply plate and wave plate. Install 3rd clutch exhaust spring and valve into driven sprocket support.

Scheme 12

1. Install input carrier assembly onto reaction internal gear with snap ring. Install thrust washer/bearing onto input carrier. Install input internal gear flange onto gear with snap ring. Install thrust washer onto flange.
2. Install forward clutch sprag assembly. Ensure direction of cage lip is correct (facing internal gear). (Scheme 14) Ensure forward sprag rotates in counterclockwise direction. (Scheme 17) Install thrust washer onto coast clutch hub. Install coast clutch hub onto flange with snap ring. Install thrust washer/bearing onto coast clutch hub.

Scheme 13

Scheme 14

Install NEW seals on clutch support. Install low-roller clutch. (Scheme 15) Turn counterclockwise as far as possible. Ensure tabs on clutch rest on face of clutch support. (Scheme 18) Ensure low-roller clutch turns in correct direction, and locks in opposite direction. (Scheme 19)

Scheme 15

Scheme 16

Scheme 17

Scheme 18

Scheme 19

1. Assemble differential side gears and thrust washers into carrier. Replace snap ring on right side gear output shaft. Using petroleum jelly, position thrust washers onto pinion gears. Assemble pinion gears and washers into carrier.
2. Rotate pinion gears into position, and install pinion shaft. Tap retaining pin into position using plastic hammer. Assemble remaining thrust washers, spacers and snap rings. Install final drive sun gear seal into sun gear with seal lip facing forward clutch. Install sun gear.

Scheme 20

Disassembly

Thoroughly clean and air dry valve bodies. Remove check balls. Remove each valve train. Position valves, springs and bushings on clean surface in order removed. Remove solenoids, sensor, screens, low-reverse servo and accumulator assemblies. (Scheme 22)and (Scheme 23).

Reassemble valve body assemblies. (Scheme 22)and (Scheme 23). Using Guide Pins (J-39630-1) and (J-39068-2), assemble lower valve body to channel plate. (Scheme 24)- (Scheme 26). Ensure NEW pressure control solenoid filter and oil pressure screen is used. After assembly, ensure all valves move freely in respective bores.

Scheme 21

Scheme 22

Scheme 23

Scheme 24

Scheme 25

Scheme 26

1. Clean and air dry oil pump. Remove secondary pump body from primary/scavenge pump assembly. These components are held together tightly by 2 roll pins. Remove oil pump shaft and secondary pump gears.
2. Remove scavenge pump body and gears from scavenge pump cover. Remove primary pump body and gears from scavenge pump cover. (Scheme 28) Remove retainer pin, ball seat and ball. Remove retainer pin, pressure regulator valve and sleeve and boost valve assembly. (Scheme 27)

Install valve train assemblies into pump body. Install and align oil pump gears with punch marks up. Ensure oil pump shaft end with 4 notches is installed into secondary pump. Assemble scavenge oil pump cover and secondary oil pump body to scavenge oil pump body.

Scheme 27

Scheme 28

TRANSAXLE REASSEMBLY

Note. All selective snap ring and thrust washer measurements taken during disassembly must be rechecked at appropriate reassembly stage. For thrust washer thrust bearing and seal location and identification, refer to appropriate illustration. (Scheme 36)or (Scheme 37).

Scheme 29

Scheme 30

Scheme 31

Scheme 32

Scheme 33

1. Install manual shaft, detent lever assembly and parking pawl, if removed. (Scheme 6) Install drive sprocket support, input speed sensor and wiring harness. see scheme 6 Install torque converter seal.
2. Install low-reverse band and ensure anchor engages band. Install support fretting ring with open end toward lower oil pan. Install oil cooler return fitting "O" ring to coast and forward clutch assembly. Using Forward/Coast Clutch Puller (J-39053), install coast and forward clutch assembly into case. (Scheme 5) Ensure anchor holes in support align with holes in case.
3. Install final drive internal gear with groove up. Install snap ring with flat side down and open end in actuator rod area. Rotate support counterclockwise against spline. (Scheme 29)
4. Install reaction carrier shell into forward clutch housing with small teeth facing down. Install 3rd clutch housing and reaction carrier assembly. Install input shaft selective thrust washer and thrust bearing on 3rd clutch housing. see scheme 4 Install 4th band and reverse clutch assembly. (Scheme 30) Ensure band pin seat engages servo pin. Install reverse clutch housing and thrust washer.
5. Install seal on drive sprocket support. Using Sizer (J-39064-2), size seal. Install backing plate, 2nd clutch plates, apply plate and wave plate. (Scheme 12)
6. Place scavenge tube seal on driven sprocket support and install driven sprocket support. Install drive chain (in same direction as removed) to drive sprocket support. Tap sprockets until seated. Place thrust washers on sprockets.
7. Install island gasket and case cover gasket. (Scheme 32) Install case cover allowing wiring harness connector to pass through opening in case cover. Install bolts in correct position and hand tighten only.
8. Check input shaft end play. see scheme 4 Install Input Shaft End Play Fixture (J-39686) to front side of transaxle. Ensure "J" tab on fixture rests on input shaft. Mount Dial Indicator Post (J-25025-7A) and Dial Indicator (J-8001-3) to check end play. Push down on handle. End play should be.004-.033" (.10-.85 mm). Input shaft thrust washers range in thickness from.089" (2.26 mm) to.195" (4.95 mm) in increments of.012" (.30 mm).
9. Tighten case cover bolts and studs in a crisscross pattern to specification. See «TORQUE SPECIFICATIONS»(ref-128968-S26296536582001110900000). Install 2 check balls. (Scheme 32) Install upper valve body. (Scheme 33) Tighten bolts beginning with center bolts and working toward outside bolts to specification. See «TORQUE SPECIFICATIONS»(ref-128968-S26296536582001110900000). Install side filter.
10. Install TCC solenoid and transaxle pressure control solenoid. Install oil pump assembly. Tighten bolts beginning with center bolts and working toward outside bolts to specification. See «TORQUE SPECIFICATIONS»(ref-128968-S26296536582001110900000). Install oil pan and tighten bolts in a star pattern. Install 4th servo. (Scheme 31) Ensure tab on servo piston aligns with slot in case (some models).
11. Ensure low-reverse band is installed in correct position. Install lower valve body and channel plate. (Scheme 34) Install bolts and tighten by hand. Remove shim stock.
12. Install oil transfer plate and hand tighten bolts. (Scheme 34) Connect wiring harness and manual valve. Tighten channel plate and oil transfer plate bolts in a crisscross pattern to specification. See «TORQUE SPECIFICATIONS»(ref-128968-S26296536582001110900000). Install scavenge screens. (Scheme 31) Install lower oil pan and gasket and tighten bolts to specification in correct sequence. (Scheme 35)
13. Assemble and install final drive, output shaft and differential carrier. Engage parking pawl to hold final drive unit. Tighten differential carrier bolts.
14. Install scavenge tube and seal. (Scheme 31) Install selective thrust washer and roller thrust bearing onto output shaft. Install extension housing and hand tighten bolts.
15. Using Dial Indicator Post (J-25025-7A) and Dial Indicator (J-8001-3), check end play. Pry up on speed sensor rotor through speed sensor hole. End play should be.006-.026" (.15-.65 mm). (Scheme 3)
16. If necessary, adjust end play with selective final drive-to-case thrust washer. See «FINAL DRIVE-TO-CASE SELECTIVE THRUST WASHER IDENTIFICATION»(ref-128968-S21097520472001110900000) table. Tighten extension housing bolts. Install oil cooler return fitting to forward and coast clutch support. Install axle seals, oil pump drive shaft, torque converter and vehicle speed sensor.

FINAL DRIVE-TO-CASE SELECTIVE THRUST WASHER IDENTIFICATION

Scheme 34

Scheme 35

Scheme 36

Scheme 37