Automatic Transmission - Overhaul & Testing - 4L80E: Other Chevrolet Pickup C3500

ON-VEHICLE SERVICE

The following components can be serviced without removing transmission from vehicle

1. Converter-To-Flexplate Bolts
2. Filler Pipe
3. Front Servo
4. Rear Servo
5. Rear Extension Housing
6. Shift Control Cable
7. Solenoids
8. Speedometer Driven Gear & Seal
9. Speed Sensors
10. Transmission Pan & Filter
11. Valve Body
12. Wiring Harness
13. 3-4 Accumulator Assemblies

VALVE BODY

See OIL PUMP & VALVE BODY under TRANSMISSION DISASSEMBLY.

QUICK CHECK

1. Check the level and condition of the transmission fluid. Check the PCM or TCM memory for any stored trouble codes. Refer to the appropriate DIAGNOSIS article. If no trouble codes are present, go to next step. If codes are present, diagnose and repair all computer-related trouble codes. Clear PCM or TCM trouble code memory.
2. Perform road test. See «ROAD TEST»(ref-25408-S40381322482001100400000) under TESTING. During road test, record shift points. If shift point timing or shifting is incorrect, go to the appropriate DIAGNOSIS article.
3. If shift(s) is too harsh or too soft, see procedures for «HYDRAULIC PRESSURE TESTS»(ref-25408-S16910962062001100400000) under TESTING. For specific complaints, see appropriate condition(s) listed under «SYMPTOM DIAGNOSIS»(ref-25408-S30061744222001100400000) .

Transmission Overheats

Low fluid or blocked radiator. TCC stuck in apply or release. Broken TCC valve spring. Cross channel leakage in pump cover. Pressure regulator stuck in high demand. Blocked oil cooler. Problem with converter limit valve assembly. Loss of fluid. Problem with stator(s) or turbine seals.

High Or Low Line Pressure

Incorrect fluid level. Oil pump assembly seals or gears damaged. Pump drive shaft damaged. Pressure regulator valve spring damaged, pressure regulator valve nicked or scored. Pressure relief valve spring damaged. Pump cover leaking (bolts loose). Force motor off or on at all times. Loose connection at PCM or TCM. Possible trouble Code 73.

Inoperative In Drive

1. Low fluid level. Low fluid pressure. Manual linkage misadjusted or disconnected. Damaged torque converter. Leaking or damaged transmission case seals or gaskets. Damaged oil pump drive shaft or pump assembly. Broken bearing, pinion or carrier. Roller clutch damaged or locked.
2. Piston or seal damaged in forward clutch assembly. Forward clutch assembly clutch plates burned or missing, or check ball capsule leaking or missing. Burned reaction plate (due to lack of lubrication), broken snap ring or worn gear teeth.
3. Rear gear set assembly pinions, internal ring gear or sun gear damaged. Main shaft damaged. Parking pawl spring broken. Turbine shaft ball not seating.

Vehicle Moves Forward In "N"

Mis-positioned or stuck manual valve. Problem with forward clutch assembly.

Engine Stall

Seized forward clutch, 4th clutch or overrun clutch assembly. TCC stuck on or dragging.

Locked in Park

Damaged parking pawl; binding, weak spring or stretched rod.

Vehicle Moves in Park

Manual linkage damaged or disconnected. Broken parking pawl spring, parking pawl or parking pawl gear assembly. Park actuator spring damaged.

Slips in Reverse

Low fluid pressure. Reverse servo seal damaged. Reverse reaction drum splines stripped.

No Reverse

Low fluid pressure. Reverse servo not correctly assembled, piston or seal damaged, or incorrect apply pin. Damaged rear band. Direct clutch assembly clutch plates burned or missing, or check ball capsule leaking or missing.

Slips in "D"

Low fluid level. Low fluid pressure.

No 1st Gear in "D4"

Low roller assembly not attached or race broken. Broken center support race or splines. Damaged case near center support. Center support snap rings not seated.

No 1st Gear in "D2" Or "D3"

Low roller assembly not attached or race broken. Broken center support race or splines. Damaged case near center support. Center support snap rings not seated. Stuck front band.

No 1st Gear in "D1"

Low roller assembly not attached or race broken. Broken center support race or splines. Damaged case near center support. Center support snap rings not seated. Broken housing, or mispositioned or broken rear band anchor pin. Misaligned detent lever.

No 1-2 Shift in "D4" (1st Gear Only)

Output or input speed sensor reads zero. Sun gear splines damaged or missing.

1st & 2nd Gear Only

Solenoid "B" stuck off or not connected to PCM or TCM. Dirt in filter, leaking "O" ring or no supply voltage to solenoid "B". Stuck 2-3 shift valve. Possible trouble Code 68, 81, 85 or 87.

1st & 4th Gear Only (Manual 2nd & 3rd Only)

Solenoid "A" stuck off. Dirt in filter, PCM or TCM not grounded, leaking "O" ring, no supply voltage to solenoid "A" or wire disconnected. Stuck 1-2 shift valve. Possible trouble Code 68, 82 or 85.

Late 1-2 Shift

Problem with input and/or output speed sensor(s). Faulty digital ratio adapter (2WD only). Incorrect PROM calibration. Possible trouble Code 24, 28 or 85.

No Engine Braking in "D1"

Problem with rear band assembly. Damaged main or output shafts.

No 2nd Gear

Intermediate clutch feed cup plug missing. Problem with intermediate clutch and center support assembly. Damaged intermediate sprag. Broken direct clutch housing or snap ring.

2nd Gear Only

Possible trouble Code 24, 53, 75 and 81.

Starts in 2nd Gear

Seized intermediate clutch plates. Problem with direct clutch or center support assemblies. Stuck 1-2 shift valve. PCM- or TCM-related problem. Possible trouble Code 82.

No 2nd Gear Braking in "D2"

Problem with direct clutch housing or front band assemblies.

No Engine Braking in "D2"

Problem with rear gear set assembly. Damaged main or output shafts.

No Overrun Braking in "D2"

Problem with overrun clutch or reaction sun gear assemblies.

No 1st Gear in "D3"

Low roller assembly not attached or race broken. Broken center support race or splines. Damaged case near center support. Center support snap rings not seated. Applied front band.

No 2nd Gear in "D3"

Intermediate clutch feed cup plug missing. Problem with intermediate clutch and center support assembly. Damaged intermediate sprag. Broken direct clutch housing or snap ring.

No 3rd Gear in "D3"

Direct clutch feed cup plug missing. Problem with direct clutch and center support assembly. Broken direct clutch housing or snap ring. Solenoid "B" stuck off. Dirt in filter, PCM or TCM not grounded, leaking "O" ring, no supply voltage to solenoid "B" or wire disconnected. Stuck 2-3 shift valve. PCM or TCM problem. Possible trouble Code 81, 85 or 87.

Starts in 3rd Gear

Seized forward clutch or oil holes in driving hub plugged. Damaged or seized direct clutch assembly.

No Engine Braking in "D3"

Damaged main shaft or main shaft bushing.

2nd & 3rd Gear Only

Stuck 1-2 shift valve. Solenoid "A" off. Dirt in filter, PCM or TCM not grounded, leaking "O" ring, no supply voltage to solenoid "A" or wire disconnected. Possible trouble Code 68, 82 or 85.

No 4th Gear

Problem with 4th clutch or overrun clutch related assemblies. 2-3 shift valve stuck. Solenoid "B" off. Dirt in filter, PCM or TCM not grounded, leaking "O" ring, no supply voltage to solenoid "B" or wire disconnected. Possible trouble Code 21, 22, 28, 68, 75 or 81.

Starts in 4th Gear

Solenoid "B" stuck on. Dirt in filter, PCM or TCM signal wire grounded. Possible trouble Code 86.

Note. Digital ratio adapter receives signals from electronic speedometer and sends them to PCM/TCM.

Incorrect Shift Points

Problem related to PCM or TCM signal inputs from TPS, speed sensors or pressure switch manifold. Faulty digital ratio adapter (2WD only). Possible trouble Code 21, 22, 24, 28 or 85. Incorrect tire size, axle ratio or PROM.

Harsh Shifts

High or low line pressures. Force motor stuck off. Accumulator piston seals damaged or piston springs missing. Accumulator cover bolts improperly tightened or gaskets mispositioned. Missing check balls. Incorrect PROM calibration. Possible trouble Code 21, 22, 24, 28, 53, 68, 73, 75, 81 or 85.

Harsh Shifts ("D" To "R")

Blocked direct lube exhaust. Forward clutch spring not working. Direct clutch snap ring broken or not seated. Plugged direct clutch check ball.

Harsh Shifts (3-4 Shift)

Binding 4th clutch spring assembly. Plugged air bleed hole. 4th clutch case bolt blocking oil feed hole.

Harsh Shifts (4-3 Shift)

4th clutch snap ring not seated. 4th clutch spring assembly not working. Plugged 4th clutch housing cup plug. 4th clutch case bolt blocking oil feed hole. Blocked direct lube exhaust port.

Harsh Shifts ("D4" To "D3", "D2" or "D1")

Overrun clutch return spring assembly not working. Plugged overrun clutch housing check ball. Snap ring not seated.

Soft Shifts

Low line pressures. Force motor stuck on. Accumulator piston seals damaged or piston springs missing. Accumulator cover bolts improperly tightened or gaskets mispositioned. PCM or TCM failure. Incorrect PROM calibration. Possible trouble Code 73.

Soft Shift (Into "R")

Plugged direct clutch oil feed. Blocked direct lube exhaust port.

Soft Shift (R To "D")

Direct clutch spring not working, large snap ring not seated or plugged check ball.

Soft Shift (2-1)

Intermediate clutch spring assembly not working. Center support snap ring not seated. Center support air bleed blocked.

Soft Shift (2-3)

Plugged direct clutch oil feed. Blocked direct lube exhaust port.

Soft Shift (3-2)

Direct clutch spring not working, small snap ring not seated or plugged check ball.

Soft Shift ("D3" To "D2")

Missing check ball. Incorrect orifice sizes.

No "D2" To "D1" Shift

Broken or disconnected rear band. Incomplete travel of detent lever.

No "D3" To "D2" Shift

Broken or disconnected front band.

No Converter Clutch Apply

Verify proper PCM or TCM operation and vehicle wiring. Damaged wiring harness or pinched wires. Brake switch not working or misadjusted. Solenoid inoperative. Oil pump valve assembly converter clutch shift valve stuck. Converter clutch apply valve stuck. Leaking solenoid "O" ring or blocked screen. Inspect torque converter for external leaks at hub weld area, or unbalanced or contaminated fluid. Turbine shaft seals damaged. Oil pump drive shaft seal damaged. Converter clutch release exhaust orifice cup plug not seated or damaged. Possible trouble Code 24, 27, 28, 37, 39, 53, 68, 75, 81 or 83.

Converter Clutch Does Not Release

PCM or TCM-controlled TCC solenoid stuck on or does not exhaust. Control valve assembly converter clutch apply valve stuck in apply position. Faulty PCM or TCM. Possible trouble Code 83.

Converter TCC Apply Soft Or Slipping

Leaking turbine shaft seals. Worn oil pump body bushing. Leaking oil hole transfer cup plug. Faulty TCC solenoid. Low fluid pressure.

Converter Clutch Apply Time Incorrect

Incorrect output speed sensor, engine speed or throttle position sensor signal. Faulty PCM or TCM. Faulty pressure switch or temperature sensor. Incorrect coolant or transmission temperature (diesel engine) signal. Possible trouble Code 14, 15, 21, 22, 24, 28, 58, 59 or 68. Problem with digital ratio adapter (2WD only). Faulty brake switch circuit or ignition module (gasoline vehicles) or faulty tachometer (diesel vehicles.)

CLUTCH & BAND APPLICATION CHART

Gear Selector Position "D" (Overdrive)

1. 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 shift speed charts as a reference for correct shift speeds. (Scheme 74)and (Scheme 75). Also note when Torque Converter Clutch (TCC) engages while in 3rd gear or overdrive. NOTE: Ensure TCC engages in 3rd gear or overdrive during the following steps. Transmission has a Pulse Width Modulated (PWM) solenoid, which may make TCC engagement point hard to detect. If necessary, a Tech 1 scan tool may be used to indicate TCC and shift solenoid operation.
2. At vehicle speeds of 40-50 MPH, quickly depress accelerator to half open position (part throttle detent downshift). TCC should release, solenoid "A" turns off, and transmission should immediately downshift to 3rd gear.
3. At vehicle speeds of 40-50 MPH, quickly depress accelerator to wide open position (full throttle detent downshift). TCC should release, solenoids "A" and "B" turn off, and transmission should immediately downshift to 2nd gear.
4. At vehicle speeds of 40-55 MPH, release accelerator pedal while moving gear selector to "3" (3rd gear) position. TCC should release, transmission should downshift to 3rd gear, and engine braking should slow vehicle.
5. Move gear selector to "D" (overdrive) position, and accelerate to 40-45 MPH. Release accelerator pedal while moving gear selector to "2" (2nd gear) position. TCC should release, transmission 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, transmission 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. The TCC should release. Note speeds at which vehicle downshifts. (Scheme 74)or (Scheme 75).

Gear Selector Position "3" (3rd Gear)

With vehicle stopped, move gear selector to "3" (3rd gear) position. Steadily increase throttle pressure to accelerate vehicle. Note speeds at which vehicle shifts into 2nd and 3rd gears. (Scheme 74)or (Scheme 75). Ensure 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 35 MPH. Transmission 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 20 MPH. Transmission should not upshift, and TCC should not engage.

Scheme 74

Note. All speeds given are in transmission output shaft RPM. Speeds are based on percent of throttle position sensor opening. Use a Tech 1 or other scan tester to monitor this data.

Scheme 75

Note. All speeds given are in transmission output shaft RPM. Speeds are based on percent of throttle position sensor opening. Use a Tech 1 or other scan tester to monitor this data.

HYDRAULIC PRESSURE TESTS

1. Before performing hydraulic pressure tests, check fluid level and condition. Check manual control linkages for correct adjustment. See «GENERAL MOTORS LIGHT TRUCKS & VANS SERVICING»(ref-55691) article. Ensure engine is properly tuned.
2. Connect a tachometer to engine and an oil pressure gauge to line pressure test port. (Scheme 76) Compare line pressure to force motor current draw. See «FORCE MOTOR VS. LINE PRESSURE»(ref-25408-S17323108702001100400000) table.

Note. Hydraulic pressure is controlled by pump output and regulated by computer-controlled force motor. Line pressure is boosted (pressure is doubled) by force motor in the "R" selector position.

Scheme 76

Line Pressure Check

Start engine, and access OVERRIDE FORCE MOTOR on Tech 1 scan tool. Increase force motor current in .1-amp increments. Record line pressure readings, compare to specs. See FORCE MOTOR VS. LINE PRESSURE table. If pressure recorded is incorrect, see the HIGH OR LOW LINE PRESSURE heading under SYMPTOM DIAGNOSIS .

FORCE MOTOR VS. LINE PRESSURE

SPEED SENSORS/REAR HOUSING

Thoroughly clean transmission exterior. Drain fluid, and remove torque converter. Place transmission in holding fixture. Remove rear extension housing. Remove speed sensors.

Rear Band Apply Pin Selection

1. Install Band Apply Selector Pin (J-21370-10) into servo bore. (Scheme 77) Mount Band Apply Pin Selector Gauge (J-38737) and selector pin on transmission. (Scheme 78) Apply 25 ft. lbs. (34 N.m) of torque to hex nut on gauge.
2. Note which step on selector pin lines up with top edge of apply pin gauge; use this information to determine pin length. (Scheme 77)and (Scheme 79). Record length for reassembly. Pins are available in various lengths. (Scheme 79)

Scheme 77

Scheme 78

Scheme 79

END PLAY CHECKS

Using Dial Indicator (J-8001), check front and rear unit end play. (Scheme 80)and (Scheme 81). Front unit end play should be.004-.022" (.10-.56 mm). Rear unit end play should be.005-.025" (.13-.63 mm). Record measurements for reassembly reference.

Scheme 80

Scheme 81

OIL PUMP & VALVE BODY

Remove oil pump assembly cover bolts. Remove oil pump assembly, gasket and thrust washer. (Scheme 90) Remove valve body assembly. see scheme 46

FORWARD & DIRECT CLUTCH

Using Clutch Remover (J-38358-A), remove forward clutch assembly. (Scheme 88) Using Clutch Remover (J-38733), remove direct clutch assembly. (Scheme 87)

INTERMEDIATE CLUTCH

Remove snap ring. Remove intermediate clutch plates and front band. (Scheme 86)

CENTER SUPPORT & REAR GEAR UNIT

1. Remove center support bolt and discard. Remove snap ring. (Scheme 85) Using Gear Assembly Remover/Installer (J-38868), Adapter (J-21364-A) and Slide Hammer Handle (J-6125-B), remove gear assembly. (Scheme 84)
2. Remove rear case snap ring. (Scheme 82) Remove rear band and thrust washer. If necessary, select proper selective thrust washer based on end play measurements. See «END PLAY CHECKS»(ref-25408-S37233773042001100400000) under TRANSMISSION DISASSEMBLY. Set thrust washer aside for reassembly.

Scheme 82

FORWARD CLUTCH

Note. Prior to checking Forward Clutch piston movement, check identification plate attached to rear of transmission case. Units with ZBP identification are set to a different specification.

1. Install rear band and thrust washer. Ensure band anchor pins engage band, and band assembly stop is in place. Install proper selective thrust washer. see scheme 46 Install rear case snap ring. Install snap ring groove into case, with snap ring opening at 9 o'clock position. (Scheme 82)
2. Using Gear Assembly Remover/Installer (J-38868), Adapter (J-21364-A) and Slide Hammer Handle (J-6125-B), install gear assembly. (Scheme 85)
3. Install upper center support snap ring with flat side down and opening at 9 o'clock position. Using Dial Indicator (J-8001), check rear unit end play. (Scheme 81) Rear unit end play should be.005-.025" (.13-.63 mm).
4. If rear unit end play is not correct, select proper size thrust washer. See «REAR END PLAY THRUST WASHER»(ref-25408-S09593093802001100400000) table. If necessary, remove center support and rear unit to change selective thrust washer.
5. Using Center Support Aligner (J-23093), push center support splines against case splines (away from rear servo). Align center support with bolt hole. Using new bolt, install center support bolt. (Scheme 84) Tighten bolt to 32 ft. lbs. (43 N.m).

REAR END PLAY THRUST WASHER

Scheme 83

Scheme 84

Scheme 85

Install intermediate clutch plates (4 steel and 4 composition). (Scheme 86) Install backing plate with flat side down. Install snap ring at 9 o'clock position. Ensure clearance between clutch plates and backing plate is.040-.107" (1.02-2.72 mm). Using Clutch Plate Aligner (J-24396), align intermediate clutch assembly.

Scheme 86

Apply air pressure into center support hole to hold intermediate clutch plates in place. Using Clutch Installer (J-38733), install direct clutch assembly and front band. (Scheme 86)and (Scheme 87). Using Clutch Installer (J-38358-A), install forward clutch assembly and thrust bearing. (Scheme 88)and (Scheme 94).

Note. Check installed height of speed sensor ring (on forward clutch housing). Top of speed sensor ring to oil pump gasket surface height should be 3.85-3.89" (98.0-99.0 mm).

Scheme 87

Scheme 88

OIL PUMP

1. Install Locating Pin (J-25025-1) at 12 o'clock position. Install oil pump gasket. (Scheme 89) Install selective thrust washer. Using Handle (J-37789), install oil pump assembly. (Scheme 90) Ensure turbine shaft spins free. Tighten oil pump mounting bolts.
2. Using Dial Indicator (J-8001), check front unit end play. (Scheme 80) Front unit end play should be.004-.022" (.10-.56 mm). If front unit end play is not correct, select proper size thrust washer. See «FRONT END PLAY THRUST WASHER IDENTIFICATION»(ref-25408-S28194995722001100400000) table. If necessary, remove oil pump assembly to change selective thrust washer.

Scheme 89

Scheme 90

FRONT END PLAY THRUST WASHER IDENTIFICATION

SPEED SENSORS & REAR HOUSING

Install and secure torque converter. Install rear extension housing. Install speed sensors.

Scheme 91

Scheme 92

Scheme 93

Scheme 94

Scheme 95