Automatic Transaxle Overhaul & Testing - 4t80-e Cadillac DeVille Concours

APPLICATION

Note. For testing/diagnostic procedures of electronic components, see AUTO TRANS DIAGNOSIS - HYDRA-MATIC 4T80-E CONTROLS - 1995 article or AUTO TRANS DIAGNOSIS - HYDRA-MATIC 4T80-E CONTROLS - 1996 article.

TRANSAXLE APPLICATION

IDENTIFICATION

All transaxles have a nameplate attached to the rear face of transaxle case. A transaxle VIN number is also stamped into right rear surface of case. (Scheme 23)

BODY CODE DESIGNATIONS

Scheme 23

DESCRIPTION

The Hydra-Matic 4T80-E transaxles are fully automatic 4-speed units consisting primarily of a 3-element hydraulic torque converter and converter clutch.

Transaxle uses 3 gear-type pumps to supply all hydraulic pressure needed for operation. A scavenge pump removes oil from the lower oil pan. This oil is pumped into the side oil pan. A primary oil pump takes oil from the side oil pan and supplies line pressure oil. A secondary oil pump takes oil from the side oil pan and supplies remaining oil for initial clutch apply, forced downshifts, wide open throttle and reverse gear operations.

The multiplied torque from torque converter is transferred to the transaxle by a sprocket and drive link assembly. Other internal components consist of 4 multiple disc clutches, a roller clutch, 2 sprag clutches, 2 bands and 2 planetary gear sets. The final drive gear and differential assemblies are bolted on end of transaxle.

The 4T80-E uses 2 electronic shift valves controlled by the Powertrain Control Module (PCM). Transaxles also use a transaxle pressure control solenoid (force motor) solenoid to control line pressure, transaxle temperature sensor, pressure switch assembly, 2 speed sensors (Vehicle Speed Sensor - VSS and Transaxle Input Sensor - TIS), and a lock-up control solenoid for Torque Converter Clutch (TCC) operation.

LUBRICATION & ADJUSTMENTS

See procedures in appropriate TRANSMISSION SERVICING - A/T article in the TRANSMISSION SERVICING section.

ON-VEHICLE SERVICE

The following components can be serviced without removing transaxle from vehicle

1. Case Side Cover Pan.
2. Converter-To-Flexplate Bolts.
3. Cooler Lines.
4. Drive Axles.
5. Final Drive Assembly.
6. Fluid Level Indicator.
7. Reverse Servo.
8. Scavenger Oil Scoop.
9. Manual Control Cable.
10. Output Shaft.
11. Solenoids "A" & "B".
12. Transaxle Input Speed Sensor.
13. Transaxle Temperature Switch.
14. Transaxle Pan.
15. Transaxle Filter.
16. Valve Body
17. Vehicle Speed Sensor.
18. Transaxle Wiring Harness.
19. 4th Servo.
20. 1-2, 3-4, Forward & Reverse Accumulator Assemblies.
21. Oil Pressure Switch Assembly.

VALVE BODY

See SIDE COVER, OIL PUMP & LOWER VALVE BODY under TRANSAXLE DISASSEMBLY.

DRIVE AXLE SHAFTS

See appropriate AXLE SHAFTS - FRONT article in the AXLE SHAFTS & TRANSFER CASES section.

OIL COOLER FLUSHING

1. If available, fill Line Flusher (J-35944) with solution, and install oil cooler and line flusher to top transaxle cooler line on transaxle. Follow manufacturer's instructions to flush oil cooler and cooler lines.
2. If line flusher is not available, flush cooler and cooler lines with a mixture of clean solvent and water. Flush cooler in both directions until all old fluid and debris are removed. If necessary, replace plugged or damaged cooler and/or lines.

TROUBLE SHOOTING

Note. For testing/diagnostic procedures of electronic components, see AUTO TRANS DIAGNOSIS - HYDRA-MATIC 4T80-E CONTROLS - 1995 article or AUTO TRANS DIAGNOSIS - HYDRA-MATIC 4T80-E CONTROLS - 1996 article.

Note. For clutch and band applications, see CLUTCH & BAND APPLICATION CHART .

QUICK CHECK

1. Check level and condition of transaxle fluid. Check PCM memory for stored codes. See «AUTO TRANS DIAGNOSIS - HYDRA-MATIC 4T80-E CONTROLS - 1995»(ref-56014) article or «AUTO TRANS DIAGNOSIS - HYDRA-MATIC 4T80-E CONTROLS - 1996»(/cadillac/deville-concours/1994-1998/remont/automatic-trans/#automatic-transaxle-diagnosis-4t80-e) article. If no codes are present, go to next step. If codes are present, diagnose and repair all PCM-related codes. Clear PCM code memory.
2. Perform road test. See «ROAD TEST»(/cadillac/deville-concours/1994-1998/remont/automatic-trans/#automatic-transaxle-overhaul-testing-4t80-e__road-test) under TESTING. Enter PCM data mode to monitor throttle angle. See appropriate 4T80-E ELECTRONIC CONTROLS article. During road test, record shift points. If shift point timing or shifting is incorrect, go to appropriate 4T80-E ELECTRONIC CONTROLS article.
3. If shift(s) is too harsh or too soft, see «HYDRAULIC PRESSURE TESTS»(/cadillac/deville-concours/1994-1998/remont/automatic-trans/#automatic-transaxle-overhaul-testing-4t80-e__hydraulic-pressure-tests) under TESTING.
4. For specific complaints, see appropriate condition(s) listed under «SYMPTOMS»(/cadillac/deville-concours/1994-1998/remont/automatic-trans/#automatic-transaxle-overhaul-testing-4t80-e) in TROUBLE SHOOTING.

Oil Out Of Vent Or Foaming

Transaxle overfilled. Oil contaminated with antifreeze or engine overheating. Oil filter "O" ring damaged or missing. Scavenger oil pump screens blocked.

High Or Low Line Pressure

Incorrect oil level. Scavenge, primary or secondary oil pump assembly seals or gears damaged. Pressure regulator valve spring damaged or pressure regulator valve nicked, scored or seized. Pressure relief valve spring damaged or ball missing. Problem with transaxle pressure control solenoid oil feed or valve stuck. Pressure switch assembly loose. Check balls missing in control valve body. Pump or case cover leaking (bolts loose). Actuator feed limit valve stuck open.

Delayed Engagement

Low fluid level. Pressure regulator valve stuck in bore. Faulty pressure switch assembly, throttle position switch or vehicle speed sensor.

No Drive In "D"

1. Low oil level or pressure. Faulty torque converter. Manual linkage misadjusted or disconnected. Manual valve stuck. Blocked valve body channels or spacer plate. Damaged oil pump drive shaft or pump assemblies. Torque converter stator roller clutch damaged. Drive link assembly damaged, drive link chain broken or sprockets and bearings damaged.
2. Forward clutch assembly clutch plates burned, clutch plates missing, check ball capsule leaking or missing. Forward piston seals cut or damaged, or shaft feed passages blocked. Damaged or incorrectly assembled forward roller sprag or sun gear assembly.
3. Output shaft damaged or drive axles incorrectly assembled into differential. damaged or loose channel plates. Parking pawl spring broken. Damaged final drive assembly or final drive sun gear, side gears, pinion gears or internal ring gear.

Slips In "R"

Low fluid level. Low line pressure. Oil pump assemblies seals or gears damaged. Damaged reverse clutch assembly or leaking servo piston seal. Oil filter screen plugged. Leaking or damaged lo/reverse band servo seals. Damaged lo/reverse band.

Scheme 24

4T80-E GEAR RATIOS

No 1st Gear

Misadjusted manual valve. Damaged lo roller clutch, forward sprag or forward clutch assembly. Leaking oil transfer sleeve. Check for codes P016, P029 and P094. Check solenoid circuits "A" and "B" for loose, open or shorted wires. Check PCM for loose grounds, loose or corroded connections. Leaking 3rd clutch housing check ball. Broken splines at 3rd clutch housing or forward clutch splined shaft.

No 1st Gear (In "2", "3", Or "D")

Missing check ball No. 6 or inoperative coast clutch. Damaged lo/reverse servo apply pin. Stuck 1-2 shift valve. Damaged or broken coast clutch splined shaft or broken support studs. Damaged or worn lo roller clutch or forward clutch piston. Leaking support housing seal rings. Forward sprag damaged. Check for DTC 94. Problem with solenoid circuit "A".

No 2nd Gear (In "2" Or "3")

Solenoid "A" stuck on. Dirt in solenoid, PCM signal to solenoid "A" grounded or signal return wire shorted to ground. Stuck 1-2 shift valve. Damaged 2nd clutch housing seals, piston or piston check ball. Burned 2nd clutch housing clutches. Mispositioned rollers or broken springs on 2nd sprag.

No 3rd Gear (In "3")

Check for codes P019, P094 or P117. Solenoid "A" or "B" stuck. Dirt in solenoid, PCM signal to solenoid "B" grounded or signal return wire shorted to ground. Leaking or missing 3rd clutch check ball. Damaged 3rd clutch housing seals, piston or piston check ball. Burned 3rd clutch housing clutches. Exhaust valve cup plug or valve improperly installed in driven sprocket support.

No 4th Gear

Check for code P094. Failed "A" solenoid ("A" solenoid off). Dirt in filter, PCM not grounded, leaking "O" ring, no supply voltage to "A" solenoid or wire disconnected. Burned or damaged 4th band. Damaged 4th band servo assembly. Misassembled 3-4 shift valve bore plug.

3rd & 4th Gear Only

Check for code P0117. Solenoid "B" stuck. Dirt in solenoid, PCM signal to solenoid "B" grounded or signal return wire shorted to ground.

No Reverse

1. Oil pressure low. Reverse servo incorrectly assembled, piston or seal damaged or apply pin incorrect. Damaged oil pump drive shaft or oil pump assemblies. Drive link assembly damaged or drive link chain broken. Burned, damaged or mispositioned reverse band. Reverse clutch assembly clutch plates burned, clutch plates missing or check ball capsule leaking or missing.
2. Reverse piston seals cut or damaged, or shaft feed passages blocked. Reverse carrier shell splines damaged. Parking pawl spring broken. Damaged final drive assembly or final drive sun gear, side gears, pinion gears or internal ring gear.

Vehicle Moves In Park

Manual linkage damaged or disconnected. Broken final drive park pawl spring, park pawl or park pawl gear in final drive internal gear assembly. Park actuator spring damaged.

Vehicle Moves In Neutral

Manual linkage damaged or disconnected. Disconnected shift linkage. Jammed forward clutch plates, piston assembly or blocked oil feed hole. Mispositioned sprocket support hub.

Harsh Neutral-To-Drive Engagement

Engine idle too high. Missing final drive internal gear snap ring. Actuator feed limit valve stuck open.

Vehicle Starts In 2nd Gear

Check for codes P016, P029 and P094. Failed "A" solenoid ("A" solenoid off). Dirt in filter, PCM not grounded, leaking "O" ring, no supply voltage to "A" solenoid or wire disconnected. Leaking or damaged pressure control solenoid. Missing check ball in driven sprocket support (high line pressure starts only).

Soft Shifts

Line pressure too low. Pressure control solenoid stuck on. Check for code P028. Leaking pressure switch assembly. Incorrect PROM.

Erratic Shifts

Leaking or damaged "O" rings at "A" or "B" solenoids.

No Engine Breaking

Misaligned oil transfer sleeve. Broken or slipping drive chain. Damaged sprockets or drive splines.

No Overrun Breaking In "3"

Oil level too low. Burned or damaged coast clutch assembly. Damaged or cracked forward clutch housing. Stuck 3-4 shift valve. Check for trouble code P094. Stuck "A" solenoid or dirt in filter.

No Overrun Breaking In "2"

Stuck, broken or burned 4th band. Damaged 4th band servo assembly. Burned or damaged coast clutch assembly. Damaged or missing coast clutch support seal rings. Check for code P028. Pressure switch assembly not working.

No Engine Breaking In "1"

Check for code P028. Pressure switch assembly not working. Burned or damaged coast clutch assembly. Damaged or missing coast clutch support check ball. Stuck, broken or burned lo/reverse band. Damaged lo/reverse band servo assembly. Missing No. 6 check ball.

No TCC

Verify proper PCM operation and vehicle wiring. Check for possible codes P016, P029, P039, P088, P090 or P117. Check the following solenoids and switches for faulty operation, dirt or binding: TCC solenoid, brake switch, PRNDL ("P"/"N" switch) and coolant temperature sensor. Also check the same solenoid and switch circuits for open or shorted wires between voltage supply or PCM. Converter clutch shift valve of control valve assembly stuck. Converter clutch apply valve stuck. Solenoid "O" ring leaking or screen blocked. Turbine shaft seals damaged. Blocked oil pressure screen. Damaged or missing TCC "O" ring.

Converter Clutch Does Not Release

Check for code P039. TCC solenoid stuck on. TCC solenoid does not exhaust. Control valve assembly converter clutch apply valve stuck open. Turbine shaft splines damaged.

Converter Ballooning

Stuck converter feed valve.

Converter Clutch Apply With Cold Engine

Check for code P059. Transaxle temperature sensor shorted.

Converter Clutch Apply Too Soft

Fluid level too low. Converter clutch feed valve stuck. Turbine shaft seals damaged or missing. Faulty TCC solenoid. Seals damaged or missing. Defective converter clutch.

CLUTCH & BAND APPLICATION CHART (4T80-E)

ELECTRONIC SELF-DIAGNOSTICS & ELECTRONIC TESTING

Note. See AUTO TRANS DIAGNOSIS - HYDRA-MATIC 4T80-E CONTROLS - 1995 article or AUTO TRANS DIAGNOSIS - HYDRA-MATIC 4T80-E CONTROLS - 1996 article.

Note. Reference to climate control read out changes are made during ROAD TEST test procedures, some models may not be able to access this information.

ROAD TEST

Note. Before road testing vehicle, engine and transmission must be at operating temperature. TCC will not engage if engine coolant has not reached 140°F (60°C).

Gear Selector Position "D" (Overdrive)

1. Enter PCM data mode to monitor throttle angle. See 4T80-E ELECTRONIC CONTROLS article. With gear selector in "D" (overdrive) position, steadily increase throttle pressure to accelerate vehicle. Note shift speed engagement points in 2nd gear, 3rd gear and overdrive gear. Use chart as a reference for proper shift speeds. (Scheme 25)- (Scheme 30). Also note Torque Converter Clutch (TCC) engagement point while in 3rd gear or Overdrive. NOTE: Ensure TCC engages in 3rd gear or overdrive during the following steps. If testing a Cadillac model and engagement point is hard to feel, use climate control panel to indicate TCC engagement and release points. See appropriate article in the ENGINE PERFORMANCE section: For 1995 vehicles, see «BASIC DIAGNOSTIC PROCEDURES»(ref-19979). For 1996 vehicles, see «BASIC DIAGNOSTIC PROCEDURES»(/cadillac/deville-concours/1994-1998/remont/testing-diagnostics/#engine-controls-basic-engine-testing-46l).
2. At vehicle speeds of 40-50 MPH, quickly depress accelerator to half-open position (part throttle detent downshift). TCC should release, and transaxle should immediately downshift to 3rd gear. DEFOG on display changes from ON to OFF.
3. At vehicle speeds of 40-50 MPH, quickly depress accelerator to wide open position (full throttle detent downshift). TCC should release, and transaxle should immediately downshift to 2nd gear. DEFOG and ECON on display changes from on to off.
4. At vehicle speeds of 40-55 MPH, release accelerator pedal while moving gear selector to the "3" (third gear) position. The TCC should release, transaxle should downshift into 3rd gear.
5. Move gear selector to the "D" (overdrive) position, and accelerate to 40-45 MPH. Release accelerator pedal while moving gear selector to the "2" (2nd gear) position. The TCC should release, transaxle should downshift to 2nd gear immediately, and engine braking should slow vehicle.
6. Move gear selector to the "D" (overdrive) position, and accelerate to 30 MPH. Release accelerator pedal while moving gear selector to "1" (1st gear) position. TCC should release, transaxle should downshift to 1st gear and engine braking should slow vehicle.
7. With gear selector in the "D" (overdrive) position, accelerate vehicle to overdrive gear with TCC applied. Release accelerator pedal, and lightly apply brakes. The TCC should release. Note speeds at which vehicle downshifts. (Scheme 25)- (Scheme 30)

Scheme 25

Scheme 26

Scheme 27

Scheme 28

Scheme 29

Scheme 30

Gear Selector Position "3" (3rd Gear)

With vehicle stopped, move gear selector to "3" (3rd gear) position and steadily increase throttle pressure to accelerate vehicle. Note speeds at which vehicle goes into 2nd and 3rd gears. (Scheme 25)- (Scheme 30). Also note when TCC engages while in 3rd gear.

Gear Selector Position "2" (2nd Gear)

With vehicle stopped, move gear selector to the "2" (2nd gear) position. Accelerate vehicle and note speed at which vehicle shifts from 1st gear to 2nd gear. Accelerate vehicle to 25 MPH. Transaxle should not shift into 3rd gear, and TCC should not engage.

Gear Selector Position "1" (1st Gear)

With vehicle stopped, move gear selector to the "1" (1st gear) position. Accelerate vehicle to 15 MPH. Transaxle should not upshift, and TCC should not engage.

PCM DATA

Enter the following modes on climate control panel, if equipped and watch operation of sensors and transaxle. See ELECTRONIC SELF-DIAGNOSTICS & ELECTRONIC TESTING . Repeat the same test steps as during road test. See ROAD TEST under TESTING.

PD74 "A" Current

Line pressure should be low with over 1 amp current. Line pressure should be high with less than 1 amp current.

PD72 Turbine

Signal should be close to engine RPM.

PD73 Slip Speed

When TCC is release, numbers around 100 should be displayed. With TCC applied, numbers around 10 should be displayed.

PD76 Ratio

Should display transaxle ratios while in specific gear range (1st - 2.96, 2nd - 1.63, 3rd - 1.00, 4th - .68, "R" - 2.13).

PD77 Transaxle Temperature

Displays transaxle temperature in degrees centigrade.

PD82 Shift Time

Displays shift time. Shift time is usually about .25 second (except for first gear).

HYDRAULIC PRESSURE TESTS

Before performing hydraulic pressure tests, check fluid level and condition. Check manual control linkages for correct adjustment. Connect oil pressure gauge to line pressure test port. (Scheme 31)

Note. Hydraulic pressure is controlled by pump output and regulated by transaxle pressure control solenoid. Line pressure is boosted to 90-300 psi (6.2-20.7 kg/cm 2 ) in "R" position. Line pressure should increase when PCM commands less duty cycle (less current) to transaxle pressure control solenoid.

1. Enter PCM data mode to monitor throttle angle. See appropriate AUTO TRANS DIAGNOSIS - 4T80-E ELECTRONIC CONTROLS article. Check for stored trouble code P076. Repair vehicle as necessary.
2. Start engine and set parking brake. Select PCM OUTPUT OVERRIDE level on display panel. Access transaxle pressure control solenoid override (PS20). Increase PCM pressure signal to transaxle pressure control solenoid. Record line pressure readings.
3. Line pressure should gradually increase after each increase in command signal. Line pressure should be 50 psi (3.4 kg/cm 2 ) at zero percent command and about 240 psi (16.5 kg/cm 2 ) at 100 percent command. (Scheme 32) If recorded pressure is incorrect, see «HIGH OR LOW LINE PRESSURE»(/cadillac/deville-concours/1994-1998/remont/automatic-trans/#automatic-transaxle-overhaul-testing-4t80-e__high-or-low-line-pressure) under TROUBLE SHOOTING.

Scheme 31

Scheme 32

REMOVAL & INSTALLATION

See appropriate TRANSMISSION REMOVAL & INSTALLATION - A/T article in the TRANSMISSION SERVICING section.

INSPECTION

Torque converter must be replaced if any of the following conditions exist

1. Evidence Of Overheating (Blue Color).
2. Damage To Pump Assembly.
3. Metal Particles Present In Oil.
4. Leaks In Hub Weld Area.
5. Crankshaft Pilot Broken Or Damaged.
6. Hub Scored Or Damaged.
7. Stator Failure.
8. Torque Converter Imbalance.
9. Engine Coolant Contamination.
10. Excessive End Play.

STALL SPEED TEST

CASE ASSEMBLY

Remove torque converter, turbine shaft "O" ring, oil pump drive shaft, output speed sensor and oil cooler fitting from extension housing. While holding servo cover in place, remove 4th servo from case. DO NOT allow servo cover to tilt during removal or case damage may occur.

FINAL DRIVE END PLAY CHECK & ASSEMBLY PROCEDURE

1. Mount Dial Indicator Post (J-39687) and Dial Gauge (J-8001-3) to check end play. Pry up on speed sensor rotor through output speed sensor hole. End play should be.006-.025" (.15-.65 mm). (Scheme 33) Record this measurement for reassembly.
2. Remove case extension, thrust washers 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 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 33

LOWER TRANSAXLE ASSEMBLY

Remove bottom oil pan and oil scavenger 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 34) Remove control valve and accumulator cover assembly.

Scheme 34

INPUT SHAFT END PLAY CHECK

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 Gauge (J-8001-3) to check end play. Push down on handle to raise input shaft. End play should be.004-.034" (.10-.85 mm). (Scheme 35) Record this measurement for reassembly.

Scheme 35

SIDE COVER, OIL PUMP & UPPER VALVE BODY

1. Remove side cover, filter and seals. Disconnect wiring harness from transaxle temperature sensor, transaxle pressure control and TCC solenoid and case connector. Remove wiring harness.
2. Remove oil pump assembly cover bolts and remove pump assemblies. Remove upper valve body and separate gasket and spacer plate.
3. Remove 2 check balls between spacer plate and transaxle case cover. Remove transaxle case cover and gaskets from transaxle case.

DRIVE LINK ASSEMBLY

Note. See COMPONENT DISASSEMBLY & REASSEMBLY for exploded views of all internal components. (Scheme 64)for thrust washer and bearing locations. (Scheme 65)for seal location and identification.

1. Remove thrust washers from sprockets. Mark position of link on drive link chain; it should be installed facing up. Pry up driven sprocket. Remove turbine shaft drive sprocket, driven sprocket and drive link chain together as an assembly. (Scheme 36)
2. Remove drive sprocket and driven sprocket supports from transaxle case. (Scheme 36)and (Scheme 37). Ensure scavenge tube seal stays in support. If not, check support for damage. Remove transaxle input speed sensor and wiring.

Scheme 36

Scheme 37

CLUTCH & BAND ASSEMBLIES

1. Remove 2nd clutch plate assembly. (Scheme 41) Remove reverse clutch support thrust washer. Remove reverse clutch housing and 2nd sprag assembly. Remove 4th band. Holding 3rd clutch housing by input shaft, remove 3rd clutch and reaction carrier assemblies. (Scheme 39) Remove reaction carrier shell.
2. Move manual control shaft from "P" position. Remove parking pawl and pivot pin assembly. Remove 2 forward and coast clutch support bolts from transaxle case. (Scheme 38) Remove oil cooler return fitting to forward and coast clutch support. CAUTION: Forward/Coast clutch assembly weighs 50 lbs., ensure appropriate lifting equipment is used.
3. Using Forward/Coast Clutch Puller (J-39053), remove clutch assemblies. (Scheme 38) Remove lo/reverse band and fretting ring.
4. Remove detent spring. Remove detent lever roller assembly. While holding detent lever in place, remove manual shaft nut. Remove detent lever and actuator rod. Discard detent lever. Remove manual shaft assembly, and case seals.

Note. If detent lever is removed, detent lever must be replaced.

Scheme 38

Cleaning & Inspection

Clean transaxle case thoroughly with solvent, and then air dry. Inspect transaxle case for damage to band lugs, snap ring grooves and drive sprocket bearings. Check for interconnected or damaged oil passages and servo bores. Inspect case for stripped threads in bolt holes or casting porosity. Repair or replace case if necessary.

Disassembly & Inspection

1. Remove snap ring, input sun gear and input sun gear thrust bearing. Remove reaction carrier assembly. Remove reaction sun gear shell assembly.
2. Remove 3rd clutch hub. Remove snap ring and backing plate. Remove clutch plates. Compress spring assembly and remove snap ring. Remove spring and retainer assembly and piston.
3. Check 3rd clutch housing for plugged feed holes. Inspect reaction carrier and sun gear for damaged teeth, scoring or warpage. Check thrust bearing for damage.
4. Check reaction carrier pinion gear end play. End play should be.004-.035" (.10-.90 mm). Check for damage to reaction carrier internal gear. (Scheme 39)

Reassembly

1. Using seal ring expander, install both seal rings. 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, install snap ring.
3. Install apply plate, clutch plates, starting with fiber and alternating, fiber-steel-fiber etc. (Scheme 39) Install backing plate with stepped side up. Install snap ring, thrust washer and 3rd clutch hub assembly.
4. Install thrust washer 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.

Scheme 39

LEGEND FOR (Scheme 39)

DO NOT wash 4th band in solvent. Inspect 4th band assembly for heat damage, lining cracks and separation. Check band stop for damage and replace if necessary.

Remove snap ring and disassemble clutch plates. Compress spring assembly and remove snap ring. Remove spring and retainer assembly and piston. (Scheme 40) If necessary, remove 2nd sprag. Spiral snap ring must be replaced if removed from 2nd sprag. Check clutch housing for plugged feed holes. Inspect clutches for wear and piston for cracks or damaged check ball. Inspect 2nd sprag for damage.

1. Install NEW seals on reverse clutch piston. Apply petroleum jelly to seals and install clutch piston into housing. Install spring and retainer assembly. Using appropriate compressor, install snap ring.
2. Install Belleville plate, steel plate and fiber plate, alternating steel, then fiber until all 6 discs are installed. Install apply plate, stepped side up and 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 40) 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 40

LEGEND FOR (Scheme 40)

1. Set clutch plates on bench. Compress spring assembly and remove snap ring. Remove spring and retainer assembly and piston. (Scheme 41) Remove 3rd clutch exhaust valve from driven sprocket support.
2. Check driven sprocket support for plugged feed holes or damage. Inspect clutches for wear and piston for cracks or damaged check ball. Inspect 3rd clutch exhaust valve for scoring.

Apply petroleum jelly to seals. To reassemble, reverse disassembly procedures.

Scheme 41

LEGEND FOR (Scheme 41)

Remove snap ring, parking lock gear and thrust washer. Remove forward clutch support assembly with lo roller clutch. (Scheme 44) Separate clutch housing from coast clutch hub and thrust washers. Remove final drive sun gear shaft. (Scheme 42)- (Scheme 44).

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. (Scheme 43) 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 42

LEGEND FOR (Scheme 42)

Scheme 43

LEGEND FOR (Scheme 43)

Disassemble clutch support. Remove and discard oil seal rings and oil cooler return seal. (Scheme 44) Inspect all parts for damage or wear. Replace worn bushing.

Install NEW seals to clutch support. Install lo roller clutch. (Scheme 44) Turn counterclockwise as far as possible. Ensure tabs on clutch rest on face of clutch support. Ensure lo roller clutch turns in correct direction and locks in opposite direction. (Scheme 45)

Scheme 44

LEGEND FOR (Scheme 44)

Scheme 45

FORWARD & COAST CLUTCH HOUSING

1. Remove snap ring from forward/coast clutch housing. Remove backing plate, forward clutch, Belleville, coast clutch and apply plates from housing. Compress spring retainer and remove snap ring.
2. Remove coast piston, apply ring, forward clutch piston and seals. (Scheme 42) Inspect clutches for wear and piston for cracks or damaged check ball.

1. Place NEW seals on forward clutch piston and install in housing. Install forward apply ring. Place NEW seals on coast clutch piston and install in housing. Install spring and retainer assembly. Using appropriate compressor, apply pressure to spring and retainer assembly and install snap ring. Install backing plate, forward clutch, Belleville, coast clutch and apply plates, in reverse order. (Scheme 42) Install clutch assembly snap ring.
2. Install thrust bearing to back side of forward/coast clutch housing. Connect forward clutch support assembled under FORWARD & COAST CLUTCH SUPPORT to forward/coast clutch housing. Assemble coast clutch hub with thrust bearing, and input internal gear and flange into forward/coast clutch housing. (Scheme 43) NOTE: When splines of coast clutch hub and forward sprag outer race are properly engaged the input carrier bushing will drop below forward/coast clutch support hub. Ensure a dull metal sound is heard during engagement.
3. Install input carrier and reaction internal gear with thrust washer onto input internal gear. Install final drive sun gear shaft. (Scheme 43)and (Scheme 44). Install thrust bearing and parking lock gear. Install snap ring.

1. Inspect final drive internal gear for damaged teeth, worn bearing surfaces, or damage to differential and pinion gears. Inspect sun gear, thrust bearings and speed sensor ring gear for wear or damage.
2. Check final drive carrier pinion gears for excessive end play. Measure end play between carrier and pinion gear thrust washer. End play should be.008-.012" (.20-.30 mm). Replace final drive carrier if clearance is not within specification.
3. Using a pin punch, drive differential pinion shaft retainer pin from carrier. Remove pinion shaft, pinion gears, and thrust washers. (Scheme 46) Remove side gears and thrust washers.
4. Remove sun gear-to-carrier thrust bearing. Using screwdriver, pry final drive sun gear from final drive carrier. Inspect all parts for damage or abnormal wear. Inspect final drive sun gear shaft for damaged splines or journals.

1. Assemble differential side gears and thrust washers into carrier. Replace snap ring on right side gear output shaft. Using petroleum jelly, stick thrust washers onto pinion gears. Assemble pinion gears and washers into carrier.
2. Rotate pinion gears into position, then install pinion shaft. Tap retaining pin into position using a 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 46

LEGEND FOR (Scheme 46)

Inspect output shaft snap ring groove, splines, journal and shaft surface for damage. Replace if necessary.

Disassembly, Inspection & Reassembly

1. Remove accumulator housing from channel plate. Remove 4 check balls. Remove accumulator spring from channel plate. (Scheme 48)
2. Remove "E" clips from accumulator shafts on top side of accumulator housing. (Scheme 47) Remove 1-2 and 3-4 accumulator assemblies (piston, "O" ring, spring and shaft).
3. Remove cover from accumulator housing.Remove forward and reverse accumulator assemblies. Check all parts for wear or damage and replace as necessary. Lubricate all NEW seals with ATF. Reverse removal procedures to reassemble.

Scheme 47

Disassembly

1. Thoroughly clean and air dry valve bodies. Remove check balls. Remove each valve train.
2. Lay valves, springs and bushings on a clean surface in the order removed. Remove solenoids, sensor, screens, servos and accumulator assemblies.

Clean valves, springs and bushings in solvent. NEVER use shop rags to clean valve body components. Inspect valves and bushings for scoring, nicks and scratches. Inspect springs for damaged or distorted coils. Inspect valve body casting for porosity, interconnected oil passages and damaged machined surfaces.

Reassemble valve body assemblies. (Scheme 48)- (Scheme 50). Using Guide Pins (J-39630-1 and J-39068-2), assemble lower valve body to channel plate. (Scheme 51)- (Scheme 53). Ensure NEW pressure control solenoid filter and oil pressure screen is used. After assembly, ensure all valves move freely in respective bores.

Note. Install oil pressure switch assembly to lower valve body. Illustration of oil pressure switch assembly is not available.

Scheme 48

LEGEND FOR (Scheme 48)

Scheme 49

Scheme 50

LEGEND FOR (Scheme 50)

Scheme 51

Scheme 52

Scheme 53

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 oil pump cover. (Scheme 55) Remove retainer pin, ball seat and ball. Remove retainer pin, pressure regulator valve and sleeve, and boost valve assembly. (Scheme 54)

Inspect pump body for porosity, interconnected oil passages, or damaged inner pump area surface or machine facing. Check oil pump gears for damage. Check oil pump shaft and thrust washer for wear or damage. Check valve parts for damage.

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 into secondary pump. Assemble scavenge oil pump cover and secondary oil pump body to scavenge oil pump body.

Scheme 54

Scheme 55

LO/REVERSE SERVO & 4TH SERVO

For lo/reverse servo information, see VALVE BODIES under COMPONENT DISASSEMBLY & REASSEMBLY. (Scheme 49) For 4th servo information, see CASE ASSEMBLY under TRANSAXLE DISASSEMBLY.

TRANSAXLE REASSEMBLY

Note. All selective snap ring and thrust washer measurements taken during disassembly must be rechecked at appropriate reassembly stage.

Scheme 56

Scheme 57

Scheme 58

Scheme 59

Scheme 60

Scheme 61

Scheme 62

1. Install manual shaft, detent lever assembly and parking pawl, if removed. Install drive sprocket support, transaxle input speed sensor and wiring harness. (Scheme 37) Install torque converter seal.
2. Install lo/reverse band and ensure anchor engages band. Install fretting ring with open end at bottom. 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 38) Ensure anchor holes in support align with holes in case.
3. Install final drive internal gear with groove up. Install snap ring with open end in scavenge tube area. Rotate support counterclockwise against spline. (Scheme 56)
4. Install reaction shell and 3rd clutch housing. Install input shaft selective washer and thrust bearing on 3rd clutch housing. (Scheme 35) Install 4th band and reverse clutch assembly. (Scheme 57) 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 waved plate.
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 roller bearings on sprockets.
7. To air check reverse, 2nd and 3rd clutches at drive sprocket support, go to next step. Install island gasket and case cover gasket. Install case cover allowing wiring harness connector to pass through opening in case cover. Install bolts in correct position and hand tighten only. (Scheme 59) Go to step 10).
8. Using 40 psi (2.7 kg/cm 2 ) of air pressure, air check clutches and servos. Reverse, 2nd and 3rd clutches may be checked at driven sprocket support. Coast and forward clutches may be checked through passage in lower case. (Scheme 60) To check Reverse clutch, 3rd clutch or 4th servo, fabricate an air checking plate. (Scheme 61)
9. Trace template as shown. (Scheme 61) Using 3/8-1/2" thick aluminum or plastic plate, cut out an air checking plate to match template. Mark and drill holes in plate. Drill bolt holes.275" (7 mm) and air holes.157" (4 mm). Bolt plate to case. Air check clutches and 4th servo. NOTE: About 90-100 psi (6.2-6.9 kg/cm 2 ) of air pressure are required to apply the 3rd clutch.
10. Check input shaft end play. (Scheme 35) 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 Gauge (J-8001-3) to check end play. Push down on handle. End play should be.004-.034" (.10-.85 mm). Input shaft thrust washers size range is.089-.195" (2.27-4.97 mm) in increments of.012" (.30 mm).
11. Tighten case cover bolts and studs in a criss-cross pattern. Install 2 check balls. (Scheme 59) Install upper valve body. (Scheme 62) Tighten bolts starting with center ones and working to outside ones. Install side filter.
12. Install TCC/VCC solenoid and transaxle pressure control solenoid. Install oil pump assembly. Tighten bolts starting with center ones and working to outside ones. Install oil pan and tighten bolts in a star pattern. Install 4th servo. (Scheme 58) Ensure tab on servo piston aligns with slot in case (some models).
13. Using a long thin piece of.025" (.60 mm) shim stock, slide lo/reverse band into position. Install lower valve body and channel plate. (Scheme 63) Install bolts and tighten by hand. Remove shim stock.
14. Install oil transfer plate and hand tighten bolts. (Scheme 63) Connect wiring harness and manual valve. Tighten channel plate and oil transfer plate bolts in a criss-cross pattern. Install scavenge screens. (Scheme 58) Install pan gasket and tighten bolts in a star pattern.
15. Assemble and install final carrier, output shaft and differential carrier. (Scheme 58) Engage parking pawl to hold final drive unit. Tighten differential carrier bolts.
16. Install scavenge tube and seal. Install selective thrust washer and roller thrust bearing onto output shaft. (Scheme 58) Install extension housing and hand tighten bolts.
17. Mount Dial Indicator Post (J-39687) and Dial Gauge (J-8001-3) to check end play. Pry up on speed sensor rotor through speed sensor hole. End play should be.006-.025" (.15-.65 mm). (Scheme 33)
18. If necessary, adjust end play with selective final drive-to-case thrust washer. See «FINAL DRIVE-TO-CASE SELECTIVE THRUST WASHER SIZES»(/cadillac/deville-concours/1994-1998/remont/automatic-trans/#automatic-transaxle-overhaul-testing-4t80-e). 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 SIZES

Scheme 63

Scheme 64

LEGEND FOR (Scheme 64)

Scheme 65

LEGEND FOR (Scheme 65)

TORQUE SPECIFICATIONS

TORQUE SPECIFICATIONS

See also:
• AUTO TRANS DIAGNOSIS - HYDRA-MATIC 4T80-E CONTROLS - 1996
• BASIC DIAGNOSTIC PROCEDURES
• SIDE COVER, OIL PUMP & LOWER VALVE BODY
• CLUTCH & BAND APPLICATION CHART
• ROAD TEST
• HYDRAULIC PRESSURE TESTS
• ELECTRONIC SELF-DIAGNOSTICS & ELECTRONIC TESTING
• HIGH OR LOW LINE PRESSURE
• CASE ASSEMBLY