Chevrolet Silverado / GMC Sierra. Service manual — part 1026

Fig. 26: Connecting J 35944 To Oil Cooler
Courtesy of GENERAL MOTORS CORP.

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.

2008 Chevrolet Silverado 1500

2008 TRANSMISSION Automatic Transmission - 4L60-E/4L65-E/4L70-E - Cab & Chassis Sierra, Cab & Chassis

Silverado, Sierra & Silverado

Fig. 27: J 35944-A Water Supply Valve ON/OFF Positions
Courtesy of GENERAL MOTORS CORP.

3. Release the trigger (1) of the J 35944-A and allow water only to rinse the oil cooler and

pipes for 1 minute. See Special Tools.

4. Turn the J 35944-A water supply valve (3) to the OFF position and turn OFF the water

supply at the faucet. See Special Tools.

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. See Special Tools. Continue, until no
water comes out of the discharge hose.

2008 Chevrolet Silverado 1500

2008 TRANSMISSION Automatic Transmission - 4L60-E/4L65-E/4L70-E - Cab & Chassis Sierra, Cab & Chassis

Silverado, Sierra & Silverado

FLOW TEST

Fig. 28: Clipping Discharge Hose To An Empty Oil Container
Courtesy of GENERAL MOTORS CORP.

1. Disconnect the hose from the oil cooler pipe. Connect the oil cooler feed pipe, bottom

connector, to the transmission for normal flow.

2. Clip the discharge hose (1) to an empty oil container.

3. Confirm the transmission is filled with automatic transmission fluid. Refer to Fluid

Capacity Specifications for the correct automatic transmission fluid capacity.

4. Start the engine with the transmission in PARK range and run for 30 seconds after fluid

begins to flow from the discharge hose (1). A minimum of 1.9 L (2 qt) must be discharged

IMPORTANT: The Flow Test must be performed after the flush to ensure

that all flushing solution and water is removed from the oil
cooling system.

2008 Chevrolet Silverado 1500

2008 TRANSMISSION Automatic Transmission - 4L60-E/4L65-E/4L70-E - Cab & Chassis Sierra, Cab & Chassis

Silverado, Sierra & Silverado

during this 30 second run time.

5. If the fluid flow meets or exceeds 1.9 L (2 quarts) in 30 seconds, connect the oil cooler feed

pipe to the bottom connector on the transmission.

6. If fluid flow is less than 1.9 L (2 qt) in 30 seconds, perform the following diagnosis:

1. Disconnect the J 35944-A discharge hose (1) from the oil cooler return pipe. See

Special Tools.

2. Disconnect the oil cooler feed pipe at the radiator.

3. Connect the J 35944-A discharge hose (1) to the oil cooler feed pipe, radiator end.

See Special Tools.

4. Clip the discharge hose (1) onto the oil drain container.

5. Start the engine with the transmission in PARK range and run for 30 seconds after

fluid begins to flow from the discharge hose (1). A minimum of 1.9 L (2 qt) must be
discharged during this 30 second run time.

7. If the amount of transmission fluid flow remains less than 1.9 L (2 qt) in 30 seconds, inspect

the oil cooler feed pipe, bottom connector, for restrictions or damage. If no condition is
found with the feed pipe, bottom connector, inspect the transmission.

CLEAN-UP

1. Disconnect the water supply hose from the J 35944-A and bleed any remaining air pressure

from the flusher tank. See Special Tools.

2. Remove the fill cap from the J 35944-A and return any unused flushing solution to its

container. See Special Tools. Rinse the J 35944-A with water. See Special Tools. Do not
store theJ 35944-A with flushing solution in it. See Special Tools.

3. After every third use, clean the J 35944-A as described in the instructions included with the

tool. See Special Tools.

4. Dispose of any waste water/solution and transmission fluid in accordance with local

regulations.

BUSHING AND MATING SHAFT INSPECTION

IMPORTANT: Proper bushing and corresponding mating shaft inspection

should be performed before replacing the bushing, shaft, and in
some cases, the component which houses the bushing.
Thoroughly clean and dry the bushing and shaft surfaces before
inspecting for damage.

2008 Chevrolet Silverado 1500

2008 TRANSMISSION Automatic Transmission - 4L60-E/4L65-E/4L70-E - Cab & Chassis Sierra, Cab & Chassis

Silverado, Sierra & Silverado