Automatic Transmission - 4L80-E/4L85-E (Introduction, Service & Replacement): Other Chevrolet Silverado 3500

Range Reference

Range Reference

Shift Solenoid Valve State and Gear Ratio

Shift Solenoid Valve State and Gear Ratio; 4L80-E

Shift Speed

Shift Speed

Transmission Range Switch Logic

Transmission Range Switch Logic

Line Pressure

Line Pressure

Component Resistance

Component Resistance

Tools Required

J 41364-A Park Neutral Switch Aligner

Scheme 437

Scheme 438

1. Apply the park brake.
2. Shift the transmission into neutral.
3. If equipped with 4-wheel drive (4WD), remove the front propeller shaft. Refer to «Propeller Shaft Replacement - Front»(ref-184221-S09162167182005082200000) in Driveline/Axle.
4. Raise and suitably support the vehicle. Refer to «Lifting and Jacking the Vehicle»(ref-184175-S17163319502005082200000) in General Information.
5. Disconnect the park/neutral position (PNP) switch electrical connector (2).
6. Remove the range selector cable end (2) from the range selector lever ball stud (1).
7. Remove the control lever to the manual shaft nut.
8. Remove the control lever from the manual shaft.
9. Remove the PNP switch bolts.
10. Remove the PNP switch from the manual shaft. If the PNP switch does not slide off the manual shaft, file the outer edge of the manual shaft in order to remove any burrs.

Scheme 439

1. Install the PNP switch to the manual shaft by aligning the switch hub flats with the manual shaft flats.
2. Slide the PNP switch onto the manual shaft until the switch mounting bracket contacts the mounting bosses on the transmission.
3. Install the PNP switch bolts finger tight.
4. Position the J 41364-A onto the PNP switch. Ensure that the two slots on the switch where the manual shaft is inserted are lined up with the lower two tabs on the tool.
5. Rotate J 41364-A until the upper locator pin on the tool is lined up with the slot on the top of the switch. Tighten: Tighten the bolts to 25 N.m (18 lb ft).
6. Remove J 41364-A from the PNP switch. If installing a new switch, remove the positive assurance bracket at this time.
7. Install the control lever to the manual shaft with the nut.
8. Install the manual shaft nut. Tighten: Tighten the nut to 25 N.m (18 lb ft).
9. Install the range selector cable end (2) to the range selector lever ball stud (1).
10. Connect the PNP switch electrical connector (2).
11. If equipped with 4WD, install the front propeller shaft. Refer to «Propeller Shaft Replacement - Front»(ref-184221-S09162167182005082200000) in Driveline/Axle.
12. Lower the vehicle.
13. Check the PNP switch for proper operation. The engine must start in the park (P) or neutral (N) positions only. If proper operation of the switch can not be obtained, replace the switch.

J 36850 Transjel®

Scheme 440

1. Raise and suitably support the vehicle. Refer to «Lifting and Jacking the Vehicle»(ref-184175-S17163319502005082200000) in General Information.
2. Remove the transmission filter. Refer to «Automatic Transmission Fluid/Filter Replacement»(ref-184171-S26501914032005082200000) .
3. Remove the reverse boost valve bushing retainer ring (2).
4. Remove the following from the reverse boost valve cylinder: The reverse boost valve bushing The reverse boost valve The pressure regulator spring retainer The pressure regulator spring The pressure regulator valve The reverse boost valve bushing

Scheme 441

1. Install the pressure regulator valve using J 36850 .
2. Pre-assemble the following parts: The reverse boost valve bushing A new reverse boost valve A new pressure regulator spring retainer The added isolator pressure regulator spring The pressure regulator spring
3. Install the pre-assembled parts into the pump bore.
4. Install the reverse boost valve bushing retainer ring while holding the reverse boost valve bushing in place. Ensure the retainer ring (2) is in the groove.
5. Install the transmission filter. Refer to «Automatic Transmission Fluid/Filter Replacement»(ref-184171-S26501914032005082200000) .
6. Fill the transmission to the proper level with Dexron® III transmission fluid. Refer to «Transmission Fluid Checking Procedure»(ref-184198-S16784281982005082200000) .

J 25025-5 Valve Body Align Pin. See Special Tools and Equipment .

Scheme 442

1. Remove the valve body. Refer to «Valve Body and Pressure Switch Replacement»(ref-184171-S11384368412005082200000) .
2. Remove the 3rd and 4th clutch accumulator housing bolts (1).
3. Remove the 3rd and 4th clutch accumulator housing (8).
4. Remove the accumulator housing gasket (6). The accumulator housing gasket may be stuck to the spacer plate (5).
5. Remove the 3rd clutch accumulator piston spring (7).
6. Remove the 4th clutch accumulator piston spring (2).
7. Remove the valve body spacer plate (5).
8. Remove the valve body to spacer plate gasket (4) from the spacer plate (5).

1. J 43911 Selector Shaft Seal Remover
2. J 43909 Selector Shaft Seal Installer

Scheme 443

1. Remove the park/neutral position (PNP) switch. Refer to «Park/Neutral Position Switch Replacement»(ref-184202-S15976129972005082200000) .
2. Ensure that the jackscrew for J 43911 is backed off and will not interfere with installation of the removal tool. Slide the seal remover tool over the selector shaft (2) with the threaded end of the tool towards the seal.
3. Rotate the J 43911 so that the threads on the end of the tool engage the steel shell (1) of the seal. Use a wrench to be sure that the removal tool is firmly attached to the seal shell.
4. Rotate the jackscrew in the clockwise direction to remove the seal from the bore. Discard the seal that was removed.

Scheme 444

1. Carefully slide a new selector shaft seal (1) over the selector shaft (2) with the wide face of the steel case facing outward. Position the seal so that it is starting to enter the seal bore.
2. Using J 43909 , remove the inner sleeve so that the tool will slide over the selector shaft.
3. Slide the J 43909 into position so that the end of the tool contacts the seal being installed. Use a mallet to strike the J 43909 and drive the new seal into the seal bore until it is seated at the bottom of the bore.
4. Install the PNP switch. Refer to «Park/Neutral Position Switch Replacement»(ref-184202-S15976129972005082200000) .
5. Fill the transmission to the proper level with DEXRON® III transmission fluid. Refer to «Transmission Fluid Checking Procedure»(ref-184197-S28503790432005082200000) .

J 21366 Converter Holding Strap

Scheme 445

1. Raise the vehicle. Refer to «Lifting and Jacking the Vehicle»(ref-184175-S17163319502005082200000) in General Information.
2. Drain the transmission fluid. Refer to «Automatic Transmission Fluid/Filter Replacement»(ref-184171-S26501914032005082200000) .
3. Remove the rear propeller shaft. Refer to «Propeller Shaft Replacement - One Piece»(ref-184221-S28715217102005082200000) or «Propeller Shaft Replacement - Two Piece»(ref-184221-S22027825012005082200000) in Propeller Shaft.
4. Support the transmission with a suitable jack.
5. Remove the transmission support. Refer to «Transmission Support Replacement»(ref-184179-S40982671802005082200000) in Frame and Underbody.
6. Remove the exhaust manifold pipe. Refer to «Exhaust Manifold Pipe Replacement (6.0L, 6.6L, and 8.1L Engines)»(ref-184230-S38273361172005082200000) in Engine Exhaust.
7. Remove the transmission mount. Refer to «Transmission Mount Replacement»(ref-184202-S03129421422005082200000) .
8. Remove the transfer case, if equipped. Refer to «Transfer Case Assembly Replacement»(ref-184201-S26621668492005082200000) in Transfer Case NVG 149-NP (One Speed Automatic) or «Transfer Case Assembly Replacement»(ref-184161-S03457298082005082200000) in Transfer Case NVG 236/246-NP8 (Two Speed Automatic).
9. Remove the range selector cable from the transmission range selector lever ball stud and bracket. Refer to «Automatic Transmission Range Selector Cable Replacement»(ref-184202-S33838582102005082200000) .
10. Disconnect the electrical harness from the park/neutral position switch, the input speed sensor, and the output speed sensor.
11. Disconnect the wire harness from the wire loom on the left side of the transmission.
12. Cut the tie strap to separate the vent hose from the wiring harness.
13. Remove the flywheel inspection cover.
14. Mark the torque converter to flywheel orientation.
15. Remove the torque converter bolts.
16. Remove the transmission heat shield.
17. Disconnect the transmission oil cooler lines from the transmission. Refer to «Transmission Fluid Cooler Line Quick Connect Fitting»(ref-184202-S22465144962005082200000) .
18. Plug the transmission oil cooler line connectors in the transmission case.
19. Remove the stud and the bolt on the right side securing the transmission to the engine.
20. Remove the remaining six studs and the one bolt securing the transmission to the engine.
21. Install the J 21366 onto the transmission bell housing to retain the torque converter.
22. Pull the transmission straight back.
23. Remove the transmission from the vehicle.
24. Flush the transmission oil cooler and lines at this time. Refer to «Automatic Transmission Oil Cooler Flushing and Flow Test (J 35944-A)»(ref-184198-S34273127512005082200000) or «Automatic Transmission Oil Cooler Flushing and Flow Test (J 45096)»(ref-184198-S05783305472005082200000) .

Scheme 446

Scheme 447

Scheme 448

1. Install the J 21366 onto the transmission bell housing to retain the torque converter.
2. Raise the transmission into place and remove the J 21366 from the transmission.
3. Slide the transmission straight onto the locating pins while lining up the marks on the flywheel and the torque converter. The torque converter must rotate freely by hand.
4. Install studs and bolt securing the transmission to the engine. Tighten: Tighten the studs and the bolt to 50 N.m (37 lb ft).
5. Install the stud and bolt on the right side securing the transmission to the engine. Tighten: Tighten the stud and the bolt to 50 N.m (37 lb ft).
6. If reusing the torque converter bolts with a 6.0L engine, clean the bolt threads and apply Loctite 242 GM P/N 12345382 (Canadian P/N 10953489), or equivalent to the threads prior to installation.
7. If reusing the torque converter bolts with a 8.1L engine, clean the bolt threads and apply Loctite 272 GM P/N 12345493 (Canadian P/N 10953488), or equivalent to the threads prior to installation.
8. Line up the marks made during removal and install the flywheel to torque converter bolts. Tighten: Tighten the bolts to 60 N.m (44 lb ft).
9. Install the torque converter cover to the transmission.
10. Install the bolts securing the torque converter cover. Tighten: Tighten the bolts to 33 N.m (24 lb ft).
11. Install the vent hose to the wiring harness using a new tie strap.
12. Connect the wiring harness to the wiring loom on the left side of the transmission.
13. Connect the electrical harness to the park/neutral position switch, the input speed sensor, and the output speed sensor.
14. Install the range selector cable to the transmission range selector lever ball stud and bracket. Refer to «Automatic Transmission Range Selector Cable Replacement»(ref-184202-S33838582102005082200000) .
15. Install the transfer case, if equipped. Refer to «Transfer Case Assembly Replacement»(ref-184201-S26621668492005082200000) in Transfer Case NVG 149-NP (One Speed Automatic) or «Transfer Case Assembly Replacement»(ref-184161-S03457298082005082200000) in Transfer Case NVG 236/246-NP8 (Two Speed Automatic).
16. Install the transmission mount. Refer to «Transmission Mount Replacement»(ref-184202-S03129421422005082200000) .
17. Install the exhaust manifold pipe. Refer to «Exhaust Manifold Pipe Replacement (6.0L, 6.6L, and 8.1L Engines)»(ref-184230-S38273361172005082200000) in Engine Exhaust.
18. Install the transmission support. Refer to «Transmission Support Replacement»(ref-184179-S40982671802005082200000) in Frame and Underbody.
19. Remove the transmission jack.
20. Install the rear propeller shaft. Refer to «Propeller Shaft Replacement - One Piece»(ref-184221-S28715217102005082200000) or «Propeller Shaft Replacement - Two Piece»(ref-184221-S22027825012005082200000) in Propeller Shaft.
21. Connect the transmission oil cooler lines to the transmission. Refer to «Transmission Fluid Cooler Line Quick Connect Fitting»(ref-184202-S22465144962005082200000) .
22. Install the transmission heat shield.
23. Install the bolts securing the heat shield to the transmission. Tighten: Tighten the bolts to 17 N.m (13 lb ft).
24. Lower the vehicle.
25. Fill the transmission to the proper level with Dexron® III transmission fluid. Refer to «Transmission Fluid Checking Procedure»(ref-184198-S16784281982005082200000) .

How to Use This Section

This section provides the following information

1. General diagnosis information on transmissions
2. Procedures for diagnosing the Hydra-Matic® transmission

When you diagnose any condition of the Hydra-Matic® transmission, begin with Diagnostic Starting Point. This procedure indicates the proper path of diagnosing the transmission by describing the basic checks. This procedure will then refer you to the locations of specific checks. After you have determined the cause of a condition, refer to Repair Instructions for repair procedures. If the faulty component is not serviceable without removing the transmission from the vehicle, refer to Unit Repair for repair information.

Basic Knowledge

Note. Do not, under any circumstances, attempt to diagnose a powertrain condition without basic knowledge of this powertrain. If you perform diagnostic procedures without this basic knowledge, you may incorrectly diagnose the condition or damage the powertrain components.

You must be familiar with some basic electronics in order to use this section of the service manual. You should also be able to use the following special tools

1. A Digital Multimeter (DMM)
2. A circuit tester
3. Jumper wires or leads
4. A line pressure gauge set

Transmission Adaptive Functions

The 4L80-E transmission uses a line pressure control system that has the ability to adapt line pressure to compensate for normal wear of the following parts

1. The clutch fiber plates
2. The springs and seals
3. The apply bands

This adaptive feature is similar to the fuel and idle control systems, where the powertrain control module (PCM) has the ability to learn and adjust for monitored system changes.

The PCM maintains information for the following transmission adaptive systems

1-2, 2-3, 3-4 Upshift Adapts - The PCM monitors the automatic transmission input shaft speed sensor (AT ISS) and the output speed sensor (OSS), to determine when the transmission has started, and completed an upshift. The PCM looks at the time from the beginning, until the completion of the upshift. If the time of the upshift was longer than a calibrated value, then the PCM adjusts the current to the transmission pressure control (PC) solenoid to increase line pressure for the next, same, upshift under identical conditions. If the time of the upshift was shorter than a calibrated value, then the PCM adjusts the current, to the transmission PC solenoid, to decrease line pressure for the next, same, upshift under identical conditions.

Clearing Transmission Adaptive Pressure (TAP)

Transmission adaptive pressure (TAP) information is displayed and may be reset using a scan tool. The adapt function is a feature of the PCM that either adds or subtracts line pressure from a calibrated base line pressure in order to compensate for normal transmission wear. The TAP information is divided into 13 units, called cells. The cells are numbered 4 through 16. Each cell represents a given torque range. TAP cell 4 is the lowest adaptable torque range and TAP cell 16 is the highest adaptable torque range. It is normal for TAP cell values to display zero or negative numbers. This indicates that the PCM has adjusted line pressure at or below the calibrated base line pressure.

Updating TAP information is a learning function of the PCM designed to maintain acceptable shift times. It is not recommended that TAP information be reset unless one of the following repairs has been made

1. Transmission overhaul or replacement
2. Repair or replacement of an apply or release component, such as the clutch, band, piston, or servo
3. Repair or replacement of a component or assembly which directly affects line pressure

Resetting the TAP values, using a scan tool, will erase all learned values in all cells. As a result, the PCM will need to relearn TAP values. Transmission performance may be affected as new TAPs are learned. Learning can only take place when the PCM has determined that an acceptable shift has occurred. The PCM must also relearn TAP values if it is replaced.

Transmission Indicators and Messages

The following transmission-related indicators and messages may be displayed on the instrument panel cluster (IPC). For a complete listing and description of all vehicle indicators and messages, refer to Indicator/Warning Message Description and Operation in Instrument Panel, Gages, and Console.

Scheme 449

The powertrain control module (PCM) energizes the torque converter clutch pulse width modulated (TCC PWM) solenoid valve, which is located on the transmission valve body. The TCC PWM solenoid valve acts on the TCC apply valve in order to control the torque converter clutch application.

The TCC PWM solenoid valve is pulse width modulated by the PCM. This means that the PCM pulses the solenoid so that the hydraulic pressure against the torque converter clutch modulates. This modulated pressure allows the TCC to slip slightly, thus keeping the TCC balanced just at the point of engagement.

One diagnostic code is associated with the TCC PWM solenoid valve Code P2761, TCC solenoid circuit - electrical, detects a fault in the TCC circuit. While Code P2761 is set, both fourth gear in hot mode and the TCC are inhibited. Shift adapts do not update and the MIL illuminates. Recovery can occur on the next ignition cycle.

Scheme 450

The pressure control (PC) solenoid valve is attached to the valve body. The valve controls line pressure by moving a pressure regulator valve against spring pressure. The PC solenoid valve takes the place of the throttle valve or the vacuum modulator, which was used on past model transmissions.

The PCM varies line pressure based on engine load. Engine load is calculated from various inputs, especially the throttle position (TP) sensor switch. Line pressure is actually varied by changing the amperage applied to the PC solenoid valve from 0 amps, high pressure, to 1.1 amps, low pressure. The PC solenoid valve current is periodically pulsed in order to prevent contamination from sticking the pressure regulator valve.

One diagnostic code is associated with the PC solenoid valve. Code P0748 sets when the PCM detects a difference of 0.16 amp or greater between the amperage commanded and actual amperage. While the code is set, the PC solenoid valve turns OFF. Recovery can occur after the next ignition cycle. Code P0748 does not sense a hydraulic condition, such as a stuck valve.

Scheme 451

The 1-2 shift solenoid (SS) valve is a normally open exhaust valve that is attached to the valve body. The PCM controls the solenoid by grounding the solenoid through an internal quad driver. The 1-2 SS valve is ON in FIRST and FOURTH gear. When commanded ON, the 1-2 SS valve redirects fluid to act on the 1-2 shift valve.

There are two PCM related diagnostic trouble codes (DTCs) associated with the 1-2 SS valve: P0751 and P0753.

The PCM monitors the 1-2 SS circuit for an open or short to ground condition. If the PCM detects an open or short to ground condition, then DTC P0753 sets. If the PCM detects an incorrect gear ratio, then DTC P0751 sets. When DTC P0753 or P0751 sets, the PCM commands maximum line pressure, freezes shift adapts from being updated, and inhibits 3-2 downshifts.

Scheme 452

The 2-3 shift solenoid (SS) valve is a normally open exhaust valve that is attached to the valve body. The PCM controls the solenoid by grounding the solenoid through an internal quad driver. The 2-3 SS valve is ON in THIRD and FOURTH gear. When commanded ON, the 2-3 SS valve redirects fluid to act on the 2-3 shift valve.

There are two PCM related diagnostic trouble codes (DTCs) associated with the 2-3 SS valve: P0756 and P0758.

The PCM monitors the 2-3 SS circuit for an open or short to ground condition. If the PCM detects an open or short to ground condition, then DTC P0758 sets. If the PCM detects an incorrect gear ratio, then DTC P0756 sets. When DTC P0758 or P0756 sets, the PCM commands maximum line pressure, freezes shift adapts from being updated, and inhibits 3-2 downshifts.

Scheme 453

The automatic transmission fluid pressure (TFP) manual valve position switch assembly is a gear range sensing device used by the PCM in order to sense which gear range has been selected by the vehicle operator. The TFP manual valve position switch assembly is located on the valve body, and consists of five pressure switches combined into one unit. The PCM applies system voltage to the TFP manual valve position switch assembly on three separate wires. These three circuits are either grounded or open, depending on which gear range has been selected, and on which combination of the five switches gave pressure applied to them.

When the vehicle is in PARK, with the key ON and the engine OFF, the normal state of the TFP manual valve position switch assembly will be DRIVE 2. When the key is ON and the engine is running, the normal state of the TFP manual valve position switch assembly is in PARK/NEUTRAL.

There are two possible combinations of the switches within the pressure switch manifold that do not represent an actual gear range. If the PCM detects either of these combinations, then a diagnostic trouble code (DTC) sets.

The PCM TFP DTC P1810 sets when the TFP switch indicates the following

1. An illegal gear range
2. DRIVE4, DRIVE2 or REVERSE position before and after start-up
3. PARK/NEUTRAL with a ratio greater than 1.05
4. REVERSE with ratio indicating outside of REVERSE
5. DRIVE4, DRIVE3, DRIVE2 or DRIVE1 with ratio indicating REVERSE

While DTC P1810 is present, the PCM assumes DRIVE4 for shift pattern, sets line pressure to maximum, freezes shift adapts, and forces TCC ON with 4th gear commanded.

Oil Pressure and Circuit Combination Table

Scheme 454

Both of the automatic transmission input shaft speed (AT ISS) and the automatic transmission output shaft speed (AT OSS) sensors are magnetic induction sensors. The input and the output sensors are accessible from the left hand side of the transmission. The AT ISS sensor is located just forward of center and the AT OSS sensor is located near the rear. A voltage signal is induced in the AT ISS sensor by serrations, which are cut in the outside diameter of the forward clutch housing. Voltage is induced in the output sensor by gear teeth, which are pressed on the outside diameter of the rear carrier assembly.

Scheme 455

The PCM uses speed information from these sensors in order to determine the following

1. Whether the engine is running
2. Vehicle speed
3. Calculation of the gear ratio
4. Calculation of TCC slip
5. Calculation of turbine speed

Code P0502 and P0503 set if a fault exists in the AT OSS sensor circuit, and the PCM calculates a default value using the AT ISS sensor values. As long as the fault remains, and the code is set, the PCM also commands maximum line pressure, freeze shift adapts, and the MIL illuminates. If the fault is removed, normal operation resumes after the next ignition cycle.

Scheme 456

The automatic transmission fluid temperature (TFT) sensor assembly is a thermistor which is mounted in the wiring harness assembly. Low transmission temperature produces high resistance, while high temperature produces low resistance. The powertrain control module (PCM) supplies a 5-volt signal to the TFT sensor assembly through an internal resistor. Then the PCM measures the voltage drop in the circuit. Voltage is high when the transmission is cold and low when the transmission is hot.

The PCM uses the TFT sensor assembly in order to regulate torque converter clutch apply, as well as shift quality.

DTCs P0711, P0712 and P0713 indicate a fault in the TFT Sensor Assembly circuit. After the vehicle has been started, transmission temperature should rise steadily and stabilize between 90-115°C (194-239°F), depending on load. All 3 DTCs cause the PCM to use a default value of 140°C (284°F), thus reacting as if the transmission were hot in either case. When DTCs P0711, P0712 or P0713 are set, the PCM freezes the shift adapts from being updated, and the malfunction indicator lamp (MIL) illuminates. Some driveability symptoms will be noticed, especially when cold.

Scheme 457

The transmission range (TR) switch is part of the park/neutral position (PNP) and backup lamp switch assembly, which is externally mounted on the transmission manual shaft. The TR switch contains four internal switches that indicate the transmission gear range selector lever position. The powertrain control module (PCM) supplies ignition voltage to each switch circuit. As the gear range selector lever is moved, the state of each switch may change, causing the circuit to open or close. An open circuit or switch indicates a high voltage signal. A closed circuit or switch indicates a low voltage signal. The PCM detects the selected gear range by deciphering the combination of the voltage signals. The PCM compares the actual voltage combination of the switch signals to a TR switch combination chart stored in memory.

Scheme 458

The transmission electrical connector is an important part of the transmission operating system. Any interference with the electrical connection can cause the transmission to set diagnostic trouble codes or affect proper operation.

The following items can affect the electrical connection

1. Bent pins in the connector from rough handling during connection and disconnection
2. Wires backing away from the pins or coming uncrimped, in either the internal or the external wiring harness
3. Dirt contamination entering the connector when disconnected
4. Pins in the internal wiring connector backing out of the connector or pushed out of the connector during reconnection
5. Transmission fluid leaking into the connector, wicking up into the external wiring harness and degrading the wire insulation
6. Moisture intrusion in the connector
7. Low pin retention in the external connector from excessive connection and disconnection of the wiring connector assembly
8. Pin corrosion from contamination
9. Damaged connector assembly

Remember the following points

1. In order to remove the connector, squeeze the two tabs toward each other and pull straight up without pulling by the wires.
2. Limit twisting or wiggling the connector during removal. Bent pins can occur.
3. Do not pry the connector off with a screwdriver or other tool.
4. Visually inspect the seals to ensure that they are not damaged during handling.
5. In order to reinstall the external wiring connector, first orient the pins by lining up the arrows on each half of the connector. Push the connector straight down into the transmission without twisting or angling the mating parts.
6. The connector should click into place with a positive feel and/or noise.
7. Whenever the transmission external wiring connector is disconnected from the internal harness and the engine is operating, DTCs will set. Clear these DTCs after reconnecting the external connector.