Automatic Transaxle Overhaul & Testing - 4t80-e Cadillac Eldorado X

APPLICATION

TRANSMISSION APPLICATIONS

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 19) Transaxle RPO code is MH1.

Scheme 19

DESCRIPTION

Hydra-Matic 4T80-E transaxle is a fully automatic 4-speed unit 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 lower oil pan. This oil is pumped into side oil pan. A primary oil pump takes oil from side oil pan and supplies line pressure oil. A secondary oil pump takes oil from side oil pan and supplies remaining oil for initial clutch apply, forced downshifts, wide open throttle and reverse gear operations.

Multiplied torque from torque converter is transferred to 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. Final drive and differential assemblies are bolted on end of transaxle.

Transaxle uses 2 electronic shift solenoids controlled by Powertrain Control Module (PCM). Transaxle also uses a pressure control solenoid (force motor) solenoid to control line pressure, fluid temperature sensor, pressure switch assembly (also referred to as Transaxle Fluid Pressure (TFP) manual valve position switch), 2 speed sensors (Vehicle Speed Sensor - VSS and Input Speed Sensor - ISS), and a lock-up control solenoid for Torque Converter Clutch (TCC) operation.

LUBRICATION

See TRANSMISSION SERVICING A/T article in the AUTOMATIC TRANS SERVICE 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. Input Speed Sensor
13. Fluid Temperature Sensor
14. Transaxle Pan
15. Transaxle Filter
16. Control 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 & UPPER VALVE BODY under TRANSAXLE DISASSEMBLY.

DRIVE AXLE SHAFTS

See appropriate AXLE SHAFT - FRONT article in the DRIVE AXLES section

1. AXLE SHAFT - FRONT (ELDORADO)
2. AXLE SHAFT - FRONT (CONCOURS DEVILLE, DEVILLE, SEVILLE)

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 tool 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.

ADJUSTMENTS

See TRANSMISSION SERVICING A/T article in the AUTOMATIC TRANS SERVICE section.

TROUBLE SHOOTING

Note. For testing and diagnostic procedures of electronic components, see AUTO TRANS DIAGNOSIS HYDRA-MATIC 4T80-E CONTROLS article in the AUTO TRANS DIAGNOSIS section.

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

QUICK CHECK

1. Check level and condition of transaxle fluid. Check PCM memory for stored codes. See «AUTO TRANS DIAGNOSIS HYDRA-MATIC 4T80-E»(/cadillac/eldorado/x-1992-2002/remont/automatic-trans/#automatic-transaxle-diagnosis-4t80-e) CONTROLS article in the AUTO TRANS DIAGNOSIS section. 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/eldorado/x-1992-2002/remont/automatic-trans/#automatic-transaxle-overhaul-testing-4t80-e__road-test) under TESTING. Using scan tool, monitor throttle angle and pressure control solenoid percent. During road test, record shift points. If shift point timing or shifting is incorrect, go to «AUTO TRANS DIAGNOSIS HYDRA-MATIC 4T80-E»(/cadillac/eldorado/x-1992-2002/remont/automatic-trans/#automatic-transaxle-diagnosis-4t80-e) CONTROLS article in the AUTO TRANS DIAGNOSIS section.
3. If shift(s) is too harsh or too soft, see «HYDRAULIC PRESSURE TESTS»(/cadillac/eldorado/x-1992-2002/remont/automatic-trans/#automatic-transaxle-overhaul-testing-4t80-e__hydraulic-pressure-tests) under TESTING. For specific complaints, see appropriate condition(s) listed under «SYMPTOMS»(/cadillac/eldorado/x-1992-2002/remont/automatic-trans/#automatic-transaxle-overhaul-testing-4t80-e__symptoms) in TROUBLE SHOOTING.

SYMPTOMS

Note. For transaxle component locations (Scheme 20)

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.

No 1st Gear

Misadjusted manual valve. Damaged lo roller clutch, forward sprag or forward clutch assembly. Leaking oil transfer sleeve. Check solenoid "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. 8 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. Problem with solenoid "A" circuit.

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")

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

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

3rd & 4th Gear Only

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 parking pawl spring, parking pawl or parking 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

Failed solenoid "A" (solenoid off). Dirt in filter, PCM not grounded, leaking "O" ring, no supply voltage to solenoid "A" 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. Leaking pressure switch assembly. Incorrect PROM.

Erratic Shifts

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

No Engine Braking

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

No Overrun Braking In "3"

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

No Overrun Braking 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. Pressure switch assembly not working.

No Engine Braking In "1"

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 the following solenoids, sensors and switches for faulty operation, dirt or binding: TCC solenoid, brake switch, PRNDL ("P"/"N" switch) and engine coolant temperature sensor. Also check 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

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

Fluid 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.

Scheme 20

CLUTCH & BAND APPLICATION CHART

ELECTRONIC SELF-DIAGNOSTICS & ELECTRONIC TESTING

Note. See AUTO TRANS DIAGNOSIS HYDRA-MATIC 4T80-E CONTROLS article in the AUTO TRANS DIAGNOSIS section.

ROAD TEST

Note. Before road testing vehicle, engine and transaxle must be at operating temperature. TCC will not engage if engine coolant has not reached 150°F (65°C).

Note. TCC may also be referred to as Viscous Converter Clutch (VCC)

Gear Selector Position "D" (Overdrive)

1. Using scan tool, monitor throttle angle. 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 appropriate shift speed chart as a reference for proper shift speeds. (Scheme 21) Also note Torque Converter Clutch (TCC) engagement point while in 3rd gear or Overdrive. NOTE: Shift points may vary due to engine operating conditions. PCM interprets numerous electronic signals from various sensors on vehicle. This may cause a variation in shift points.
2. At vehicle speeds of 40-55 MPH, quickly depress accelerator to half-open position (part throttle detent downshift). TCC should release, and transaxle should immediately downshift to 3rd gear.
3. At vehicle speeds of 40-55 MPH, quickly depress accelerator to wide open position (full throttle detent downshift). TCC should release, and transaxle should immediately downshift to 2nd gear.
4. At vehicle speeds of 40-55 MPH, release accelerator pedal while moving gear selector to the "3" (third gear) position. TCC should release and transaxle should downshift into 3rd gear.
5. Move gear selector to "D" (overdrive) position, and accelerate to 40-45 MPH. Release accelerator pedal while moving gear selector to the "2" (2nd gear) position. TCC should release, transaxle should downshift to 2nd gear immediately, and engine braking should slow vehicle.
6. Move gear selector to "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 "D" (overdrive) position, accelerate vehicle to overdrive gear with TCC applied. Release accelerator pedal, and lightly apply brakes. TCC should release. Note speeds at which vehicle downshifts. (Scheme 21)

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 shifts into 2nd and 3rd gears. (Scheme 21) Also note when TCC engages while in 3rd gear.

Gear Selector Position "2" (2nd Gear)

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

Scheme 21

HYDRAULIC PRESSURE TESTS

Before performing hydraulic pressure tests, check fluid level and condition. Check manual control linkages for correct adjustment. Remove oil plug from line pressure test port on transaxle case. Install adapter with hole positioned at one o'clock direction. (Scheme 22) Install pipe fitting. Attach oil pressure gauge to pipe fitting.

Note. Hydraulic pressure is controlled by pump output and regulated by 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. Connect scan tool to DLC. Check for DTC P0748 (Pressure Control Solenoid Electrical Malfunction). If specific DTC or other DTCs are present, diagnose as necessary. If DTCs are not present, place gear selector in "P" position and set parking brake. Start engine and allow vehicle to reach normal operating temperature.
2. Using scan tool, enter diagnostic mode. Select "MISC TESTS". Select "A/T OUTPUTS-PC SOLENOID". Using scan tool, increase transaxle fluid pressure by commanding low amperage to pressure control solenoid. Read corresponding line pressure on oil pressure gauge. 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 23) If recorded pressure is incorrect, see HIGH OR LOW LINE PRESSURE under «TROUBLE SHOOTING»(/cadillac/eldorado/x-1992-2002/remont/automatic-trans/#automatic-transaxle-overhaul-testing-4t80-e__trouble-shooting).

Scheme 22

Scheme 23

REMOVAL & INSTALLATION

See TRANSMISSION REMOVAL & INSTALLATION - A/T article in the AUTOMATIC TRANS SERVICE 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

NOISE TEST

1. Torque converter whine is usually noticed when vehicle is stopped and transaxle is in Reverse or Drive. Whine will increase when engine RPM is increased and will stop when vehicle is moving or when torque converter clutch is applied. Stall test is to ensure whine is coming from torque converter.
2. Start engine, and allow it to reach normal operating temperature. Apply parking and service brakes. Put transaxle in Drive. Depress accelerator to about 1200 RPM for less than 6 seconds. DO NOT depress accelerator for more than 6 seconds or transaxle damage may occur. Torque converter noise will increase under this load.

Note. Torque converter whine should not be confused with pump whine, which is usually noticeable in Park, Neutral and all other gear ranges. Pump whine will vary with pressure.

STATOR CHECK

1. Torque converter stator roller clutch can either remain locked up at all times or freewheel in both directions. If stator is freewheeling at all times, vehicle tends to have poor acceleration from a stop. Vehicle may act normal at speeds above 30-35 MPH.
2. If poor acceleration is noted, ensure exhaust system is not blocked, engine timing is correct and transaxle is in 1st gear when starting from a stop. If stator is locked up at all times, performance from a stop appears normal. Engine RPM and acceleration is limited at high speeds. Engine may overheat from this condition.
3. A visual inspection of torque converter may reveal converter is Blue from overheating. If torque converter has been removed from vehicle, stator roller clutch can be checked by inserting 2 fingers into splined inner race of roller clutch and trying to turn race in both directions. Inner race should turn freely clockwise but should not turn or should be difficult to turn counterclockwise.

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. Use Dial Indicator Post (J-25025-7A) and Dial Indicator (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-.64 mm). (Scheme 24) 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 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 24

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 25) Remove control valve and accumulator cover assembly.

Scheme 25

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 Indicator (J-8001-3) to check end play. Push down on handle to raise input shaft. End play should be.004-.034" (.10-.86 mm). (Scheme 26) Record this measurement for reassembly.

Scheme 26

SIDE COVER, OIL PUMP & UPPER VALVE BODY

1. Remove side cover, filter and seals. Disconnect wiring harness from fluid temperature sensor, pressure control solenoid, TCC solenoid and case connector. Remove wiring harness.
2. Remove oil pump assembly cover bolts. (Scheme 54) Remove pump assemblies. Remove upper valve body and separate gasket and spacer plate. Remove 2 check balls between spacer plate and case cover. Remove case cover and gaskets from transaxle case.

DRIVE LINK ASSEMBLY

Note. See COMPONENT DISASSEMBLY & REASSEMBLY for exploded views of all internal components. (Scheme 56)for thrust washer and thrust bearing locations. (Scheme 57)for seal location and identification.

1. Remove thrust washers from sprockets. Grab drive link chain above drive sprocket and pull toward transaxle case. Measure drive link chain clearance to case. If clearance is less than.50" (12.7 mm), replace drive link chain.
2. Mark position of drive link chain for reassembly reference. Noise may occur if chain is not installed in same direction as removed. Pry up driven sprocket. Remove turbine shaft and drive sprocket, driven sprocket and drive link chain together as an assembly. (Scheme 27)
3. Remove drive sprocket and driven sprocket supports from transaxle case. (Scheme 27)and (Scheme 29). Ensure scavenge tube seal stays in support. If not, check support for damage. Remove input speed sensor and wiring harness.

Scheme 27

Scheme 28

CLUTCH & BAND ASSEMBLIES

1. Remove 2nd clutch plate assembly. (Scheme 33) 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 31) Remove reaction carrier shell.
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 29) Remove oil cooler return fitting to forward and coast clutch support. CAUTION: If oil cooler return fitting is NOT removed from forward and coast clutch support, damage to transaxle case may result.
3. Using Forward/Coast Clutch Puller (J-39053), remove clutch assemblies. (Scheme 29) Remove lo/reverse band and support fretting ring. (Scheme 36)
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 30)

Scheme 29

Scheme 30

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 and retainer. Remove spring and retainer assembly and piston. Remove seal rings from 3rd clutch housing (if necessary).
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. Using feeler gauge, measure end play between reaction carrier housing and planetary pinion gear. End play should be.004-.035" (.10-.89 mm). Check for damage to reaction carrier internal gear. (Scheme 31)

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, starting with friction and alternating with steel plate. (Scheme 31) 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. Apply 50-60 psi to ensure proper operation of 3rd clutch. (Scheme 52)

Scheme 31

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 and retainer seat. Remove spring and retainer assembly and piston. (Scheme 32) 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. Install retainer seat. Using appropriate compressor, install snap ring.
2. Install Belleville plate. Install 3 steel plates and 3 friction plates, starting 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 2nd sprag race and ensure housing turns counterclockwise. (Scheme 32) 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 32

1. Set clutch plates on bench. Compress spring assembly and remove snap ring. Remove spring assembly and piston. (Scheme 33) 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 33

Remove snap ring, parking lock gear and thrust bearing. Remove forward clutch support assembly with lo roller clutch. (Scheme 36) Separate clutch housing from coast clutch hub and thrust washers. Remove final drive sun gear shaft. (Scheme 34)-19.

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 35) 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 34

Scheme 35

Disassemble clutch support. Remove and discard oil seal rings and oil cooler return seal. (Scheme 36) Inspect all parts for damage or wear. Replace worn bushing.

Install NEW seals to clutch support. Install lo roller clutch. (Scheme 36) 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 37)

Scheme 36

Scheme 37

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 assembly and remove snap ring.
2. Remove coast clutch piston, apply ring, forward clutch piston and seals. (Scheme 34) 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 clutch apply ring. Place NEW seals on coast clutch piston and install in housing. Install spring assembly. Using appropriate compressor, apply pressure to spring assembly and install snap ring. Install backing plate, forward clutch, Belleville, coast clutch and apply plates, in reverse order. (Scheme 34) 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»(/cadillac/eldorado/x-1992-2002/remont/automatic-trans/#automatic-transaxle-overhaul-testing-4t80-e) to forward/coast clutch housing. Assemble coast clutch hub with thrust bearing, and input internal gear and flange into forward/coast clutch housing. (Scheme 35) 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. Distance from top edge of forward/coast clutch housing to top edge of input internal gear is about.886" (22 mm).
3. Install input carrier and reaction internal gear with thrust washer onto input internal gear. Install final drive sun gear shaft. (Scheme 35)and (Scheme 37). 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 retaining pin from carrier. Remove pinion shaft, pinion gears, and thrust washers. (Scheme 38) 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 38

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 40)
2. Remove "E" clips from accumulator shafts on top side of accumulator housing. (Scheme 39) 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. To reassemble, reverse disassembly procedure.

Scheme 39

Disassembly

Thoroughly clean and air dry valve bodies. Remove check balls. Remove each valve train. Lay valves, springs and bushings on a clean surface in the order removed. Remove solenoids, sensor, screens, lo/reverse servo and accumulator assemblies. (Scheme 41)and (Scheme 43).

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 41)and (Scheme 43). Using Guide Pins (J-39630-1 and J-39068-2), assemble lower valve body to channel plate. (Scheme 43)-28. 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 not available.

Scheme 40

Scheme 41

Scheme 42

Scheme 43

Scheme 44

Scheme 45

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 47) Remove retainer pin, ball seat and ball. Remove retainer pin, pressure regulator valve and sleeve, and boost valve assembly. (Scheme 46)

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

Scheme 46

Scheme 47

LO/REVERSE SERVO & 4TH SERVO

For lo/reverse servo disassembly procedure, see VALVE BODIES under COMPONENT DISASSEMBLY & REASSEMBLY. (Scheme 41) For 4th servo disassembly procedure, 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 48

Scheme 49

Scheme 50

Scheme 51

Scheme 52

Scheme 53

Scheme 54

1. Install manual shaft, detent lever assembly and parking pawl, if removed. (Scheme 30) Install drive sprocket support, input speed sensor and wiring harness. (Scheme 28) Install torque converter seal.
2. Install lo/reverse band and ensure anchor engages band. Install support 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 29) 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 48)
4. Install reaction carrier shell and 3rd clutch housing. Install input shaft selective thrust washer and thrust bearing on 3rd clutch housing. (Scheme 26) Install 4th band and reverse clutch assembly. (Scheme 49) 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 33)
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. 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 51) Go to step 10).
8. Using 50-60 psi (2.7 kg/cm 2 ) of air pressure, air check clutch assemblies. 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 52) To check 4th servo, fabricate an air checking plate. (Scheme 53)
9. Trace template as shown. (Scheme 53) 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 4th servo. Reverse clutch and 2nd clutch can also be air checked using plate.
10. Check input shaft end play. (Scheme 26) 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-.034" (.10-.86 mm). Input shaft thrust washers size range is.089-.195" (2.26-4.95 mm) in increments of.012" (.30 mm).
11. Tighten case cover bolts and studs in a crisscross pattern. Install 2 check balls. (Scheme 51) Install upper valve body. (Scheme 54) Tighten bolts starting with center bolts and working to outside bolts. Install side filter.
12. Install TCC/VCC solenoid and transaxle pressure control solenoid. Install oil pump assembly. Tighten bolts starting with center bolts and working to outside bolts. Install oil pan and tighten bolts in a star pattern. Install 4th servo. (Scheme 50) Ensure tab on servo piston aligns with slot in case (some models).
13. Using a long thin piece of.025" (.64 mm) shim stock, slide lo/reverse band into position. Install lower valve body and channel plate. (Scheme 55) Install bolts and tighten by hand. Remove shim stock.
14. Install oil transfer plate and hand tighten bolts. (Scheme 55) Connect wiring harness and manual valve. Tighten channel plate and oil transfer plate bolts in a crisscross pattern. Install scavenge screens. (Scheme 50) Install pan gasket and tighten bolts in a star pattern.
15. Assemble and install final drive, output shaft and differential carrier. (Scheme 50) 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 50) Install extension housing and hand tighten bolts.
17. Use Dial Indicator Post (J-25025-7A) and Dial Indicator (J-8001-3) to check end play. Pry up on speed sensor rotor through speed sensor hole. End play should be.006-.025" (.15-.64 mm). (Scheme 24)
18. If necessary, adjust end play with selective final drive-to-case thrust washer. See FINAL DRIVE-TO-CASE SELECTIVE THRUST WASHER SIZES 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 SIZES

Scheme 55

Scheme 56

Scheme 57

TORQUE SPECIFICATIONS

TORQUE SPECIFICATIONS

WIRING DIAGRAMS

Note. See AUTO TRANS DIAGNOSIS HYDRA-MATIC 4T80-E CONTROLS article in the AUTO TRANS DIAGNOSIS section.

See also:
• AUTO TRANS DIAGNOSIS HYDRA-MATIC 4T80-E
• SIDE COVER, OIL PUMP & UPPER VALVE BODY
• CLUTCH & BAND APPLICATION CHART
• ROAD TEST
• HYDRAULIC PRESSURE TESTS
• SYMPTOMS
• TROUBLE SHOOTING
• CASE ASSEMBLY