GM Service Manual Online
For 1990-2009 cars only

Flushing Procedure

Tools Required

    • J 35944-A Transmission Oil Cooler and Line Flusher
    • J 35944-22 Cooler Flushing Fluid

    Notice: Whenever you remove the transmission for service, you must perform the automatic transmission oil cooler flushing procedure in order to remove the existing fluid which may be contaminated. This will prevent contamination of the new fluid. You must perform the flushing procedure after the removal of the old transmission and before the installation of the overhauled or replacement transmission.

    Notice: Only use J 35944-20 Cooler Flushing Fluid with the J 35944-A Oil Cooler and Line Flusher. Use of any other fluid can result in damage to the tool, damage to the automatic transmission oil cooler components, or improper flushing of the cooler.

    Important: Do not overfill the tool and follow the manufacturer's procedures for handling the fluid.

  1. Remove the fill cap on the J 35944-A and fill with 0.6 liters (20-21 oz) of J 35944-22 .
  2. Replace the cap on the J 35944-A and pressurize to 550-700 kPa (80-100 psi).
  3. Install the J 35944-A to the vehicle undercarriage with the hook provided.

  4. Object Number: 106262  Size: SH
  5. Attach the hose from the flushing tool with the top fitting at the transmission end of the oil cooler pipe.
  6. Install the discharge hose to the bottom fitting at the transmission end of the oil cooler pipe. Clip the opposite end of the discharge hose to the oil drain container.
  7. With the water valve on the J 35944-A in the Off position, attach the water supply to the tool.
  8. Turn on the water supply at the faucet.
  9. Important: If the water does not flow through the cooler, the system is completely plugged. Do not complete the flushing procedure. Turn the water off immediately and inspect the cooler and upper and lower pipes for restriction. Replace the cooler and cooler pipes as required.

  10. Flush the fluid by opening the water valve on the tool to the On position for about 10 seconds.
  11. Turn the water valve on the tool to the Off position.
  12. Clip the discharge hose to a 5-gallon pail. Cover the pail with a shop cloth in order to prevent splashing.
  13. Turn the water valve on the tool to the On position and depress the trigger in order to mix the flushing fluid into the water flow. Use the bail clip in order to hold the trigger down.
  14. Flush the cooler with water and fluid for two minutes. Every 15-20 seconds during the flushing procedure, attach the air supply to air valve on the J 35944-A and leave in place for 3-5 seconds in order to create a surging action for complete cleaning.
  15. Release the trigger, and turn the water valve on the tool to the Off position.
  16. Disconnect both hoses from the upper and lower pipes.
  17. Connect the hose from the flushing tool to the bottom fitting at the transmission end of the oil cooler pipe.
  18. Connect a discharge hose to the top fitting at the transmission end of the oil cooler pipe. Reversing hoses will create a backflush.
  19. Turn the water valve on the tool to the On position and depress the trigger in order to mix the flushing fluid into the water flow. Use the bail clip in order to hold the trigger down.
  20. Flush the cooler with water and fluid for two minutes. Every 15-20 seconds during the flushing procedure, attach the air supply to air valve on the J 35944-A and leave in place for 3-5 seconds in order to create a surging action for complete cleaning.
  21. Release the trigger and allow the water to rinse the cooler for only one minute.
  22. Turn the water valve on the tool to the Off position, and turn the water supply Off at the faucet.
  23. Attach an air supply to air valve on the J 35944-A and dry the system out with dry compressed air for at least two minutes. Ensure that no moisture can be seen leaving the hose. Use an air chick clip, if available, in order to secure the air chuck onto the air valve for ease of operation.
  24. Remove the J 35944-A and discharge the hose from the upper and lower pipes.