Automatic Transmission - 4L80-E/4L85-E (Troubleshooting): Maintenance Chevrolet Silverado 3500

Transmission Fluid Checking Procedure

1. Start the engine and operate the vehicle for 15 minutes or until the transmission fluid reaches an operating temperature of 82-93°C (180-200°F).
2. Park the vehicle on a level surface.
3. With your foot on the brake, move the shift lever through each gear range. Pause for about three seconds in each range, ending in Park.
4. Apply the parking brake and let the engine idle for 3 minutes.
5. Remove the transmission fluid level indicator. Wipe the indicator clean. Insert the indicator. Give the indicator a full twist in order to close.
6. Wait 3 seconds and remove the indicator.
7. Read both sides of the indicator. The fluid must be within the hot cross-hatched area using the lowest level reading.

Transmission Fluid Checking Procedure

Possible Points of Fluid Leaks

Transmission Oil Pan

1. Incorrectly tightened oil pan bolts
2. Improperly installed or damaged oil pan gasket
3. Damaged oil pan or mounting face
4. Incorrect oil pan gasket

Case Leak

1. Damaged or missing fill tube seal
2. Mislocated fill tube bracket
3. Damaged vehicle speed sensor seal
4. Damaged manual shaft seal
5. Loose or damaged oil cooler connector fittings
6. Worn or damaged propeller shaft oil seal
7. Loose line pressure pipe plug
8. Porous casting warped torque converter housing

Leak at the Torque Converter End

1. Converter leak in the weld area
2. Converter seal lip cut. Check the converter hub for damage
3. Converter seal bushing moved forward and damaged
4. Converter seal garter spring missing from the seal
5. Porous casting of the transmission case or the oil pump

Leak at the Vent Pipe or the Fluid Fill Tube

1. Overfilled system
2. Water or coolant in the fluid. The fluid will appear milky
3. Transmission case porous
4. Incorrect fluid level indicator
5. Plugged vent
6. Drain-back holes plugged
7. Mispositioned oil pump to case gasket, if equipped

Scheme 472

Back Flush

1. Inspect the transmission oil cooler pipes for kinks or damage. Repair as necessary.
2. Connect the J 35944-A to the oil cooler feed front connector. Use the J 35944-200 , if required.
3. Clip the discharge hose (2) onto the oil drain container.
4. Attach the J 35944-A to the undercarriage of the vehicle with the hook provided and connect the flushing system feed supply hose (1) from the J 35944-A to the rear connector oil cooler return pipe. Use the J 35944-200 , if required.
5. Turn the J 35944-A water supply valve (3) to the ON position and allow water to flow through the oil cooler and pipes for 10 seconds to remove any remaining transmission fluid. If water does not flow through the oil cooler and pipes, the cause of the blockage must be diagnosed and the plugged component must be repaired or replaced. Continue with the cooler flushing and flow check procedure once the blockage is corrected.
6. Turn the J 35944-A water supply valve (3) to the OFF position and clip the discharge hose onto a 19 liter (5 gallon) pail with a lid, to avoid splashback.
7. Turn the J 35944-A water supply valve (3) to the ON position and depress the trigger (1) to mix cooler flushing solution into the water flow. Use the clip provided on the handle to hold the trigger (1) down. The discharge will foam vigorously when the solution is introduced into the water stream.
8. Flush the oil cooler and pipes with water and solution for 2 minutes. During this flush, attach the shop air supply 825 kPa (120 psi) to the flushing system feed air valve (2) located on the J 35944-A , for 3-5 seconds at the end of every 15-20 second interval to create a surging action.
9. Release the trigger (1) and turn the J 35944-A water supply valve (3) to the OFF position.

Scheme 473

1. Disconnect both hoses (1 and 2) from the oil cooler pipes and connect them to the opposite oil cooler pipe. This will allow the oil cooler and pipes to be flushed in the normal flow direction.
2. Repeat Step 6 and 7 of the Back Flush.
3. Release the trigger (1) of the J 35944-A and allow water only to rinse the oil cooler and pipes for 1 minute.
4. Turn the J 35944-A water supply valve (3) to the OFF position and turn OFF the water supply at the faucet.
5. Attach the shop air supply to the flushing system feed air valve (2) on the J 35944-A and blow out the water from the oil cooler and pipes. Continue, until no water comes out of the discharge hose.

Cooler Flow Check and Flushing Steps

1. Machine Set-up
2. Determine Minimum Flow Rate
3. Back Flush
4. Forward Flush
5. Flow Test
6. Code Recording Procedure
7. Clean-up

Tools Required

1. J 35944-200 Cooler Flushing Adapter
2. J 45096 Transmission Oil Cooling System Flush and Flow Test Tool
3. Shop air supply with water/oil filters, regulator and pressure gage - minimum 90 PSI (621 kPa)
4. Eye protection
5. Rubber gloves

Scheme 474

Scheme 475

1. Verify that the main power switch (1) is in the OFF position.
2. Place the main function switch (2) in the IDLE position.
3. Connect J 45096 to the vehicle 12 V DC power source by connecting the red battery clip to the positive, +, battery post on the vehicle and connect the negative lead to a known good chassis ground.
4. Turn the main power switch to the ON position.
5. Fill the supply tank with DEXRON®III/Mercon®, or equivalent, through the fill port.
6. Install and tighten the fill cap.
7. Connect a shop air supply hose to the quick-disconnect on the rear panel marked SUPPLY AIR.

Scheme 476

1. From the machine display, identify the temperature of the automatic transmission fluid that is stored in the supply vessel of J 45096 .
2. Determine whether the transmission oil cooler is steel or aluminum by using a magnet (1) at the cooler flange (2) at the radiator.
3. Refer to the table below. Using the temperature from Step 1, locate on either the Steel MINIMUM Flow Rate table or the Aluminum MINIMUM Flow Rate table the minimum flow rate in gallons per minutes (GPM). Record the minimum flow rate in GPM and the supply fluid temperature for further reference. Example:: Fluid temperature: 75°F Cooler type: Steel The MINIMUM flow rate for this example would be 0.8 GPM.
4. Inspect the transmission oil cooler lines for damage or kinks that could cause restricted oil flow. Repair as needed and refer to the appropriate GM service manual procedures.

Minimum Flow Rate in Gallons Per Minute (GPM)

Scheme 477

1. Connect the J 45096 adapters (1) to the vehicle's transmission oil cooler supply and return lines at the transmission. It may require the use of J 35944-200 cooler flushing adapter.
2. Connect the black supply hose (1) to the return line, rear connector of the transmission, and the clear waste hose (2) to the feed line, front connector of the transmission, to the vehicle cooler lines. This is the reverse flow - backflush direction.
3. Turn the main function switch to the FLUSH position. Allow the machine to operate for 30 seconds.
4. Turn the main function switch to the IDLE position and allow the supply vessel pressure to dissipate.

Forward Flush

1. Disconnect the supply and waste hoses from the vehicle cooler lines. Reverse the supply and waste hoses to provide a normal flow direction.
2. Turn the main function switch to the FLUSH position and allow machine to operate for 30 seconds.

Automatic Transmission Fluid Leaks

Automatic Transmission Fluid Leaks

Inadequate Lubrication at Low Line or Heavy Loads

Inadequate Lubrication at Low Line or Heavy Loads

Inadequate Lubrication

Inadequate Lubrication

Fluid Foaming

Fluid Foaming