Hummer H2. Manual - part 2464

Courtesy of GENERAL MOTORS CORP.

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.  

Forward Flush 

IMPORTANT: Flushing for approximately 2 minutes in each cooler line direction will 

result in a total of about 30-38 L (8-10 gallons) of waste fluid. This mixture 
of water and flushing fluid is to be captured in a bucket or similar 
container.

 

2004 Hummer H2 

2004 TRANSMISSION Automatic Transaxle - 4L60-E/4L65-E (Troubleshooting)

  

Fig. 27: Flushing Oil Cooler & Lines 
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. 

 

2004 Hummer H2 

2004 TRANSMISSION Automatic Transaxle - 4L60-E/4L65-E (Troubleshooting)

  

Fig. 28: Turning J 35944-A Water Supply Valve To ON Position 
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.  

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.  

Flow Test 

 

2004 Hummer H2 

2004 TRANSMISSION Automatic Transaxle - 4L60-E/4L65-E (Troubleshooting)

  

Fig. 29: 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 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.  

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.

 

2004 Hummer H2 

2004 TRANSMISSION Automatic Transaxle - 4L60-E/4L65-E (Troubleshooting)