GM Service Manual Online
For 1990-2009 cars only

Flushing Procedure

Tools Required

    • J 35944-A Transmission Oil Cooler and Line Flushing Tool
    • J 35944-22 Cooler Flushing Fluid
  1. Remove the fill cap on the J 35944-A and fill with 0.6 liter (20 oz) of the J 35944-22 .
  2. • Do not overfill.
    • Follow the manufacturer's suggested procedures for handling the solution.
  3. Install the cap on the J 35944-A and pressurize the J 35944-A to 550-700 kPa (80-100 psi).
  4. Connect the J 35944-A to the transmission end of the oil cooler pipe that feeds the bottom fitting of the oil cooler.
  5. Connect the discharge hose to the top oil cooler pipe.
  6. Clip the discharge hose to the oil drain container.
  7. With the water valve on the J 35944-A in the OFF position, connect the water supply to the tool.
  8. Turn on the water supply.
  9. Notice: If water does not flow through the oil cooler (system is completely plugged), do not continue the flushing procedure, or damage to the tool or components could result. Turn the water OFF immediately. Inspect the pipes and the cooler for restrictions. Replace the oil pipe(s) and/or the oil cooler.

  10. Flush the transmission fluid by opening the water valve to the ON position for 10 seconds.
  11. Close the water valve and clip the discharge hose to a 5 gallon pail.
  12. Cover the pail with a shop towel in order to prevent splash.
  13. Turn the water valve to the ON position and depress the trigger in order to mix the flushing solution into the water flow.
  14. Use the bale clip provided in order to hold the trigger down.
  15. Flush the cooler with water and the solution for 2 minutes. During this flush, attach an air supply to the air valve located on the tool for 3 to 5 seconds every 15 to 20 seconds. This will create a surging action to ensure complete cleaning.
  16. Release the trigger and turn off the water valve.
  17. Disconnect both hoses from the oil cooler pipes in order to perform an initial flush.
  18. Reconnect the hoses to the pipes opposite the initial flush to do a backflush.
  19. Turn the water valve to the ON position and depress the trigger in order to mix the flushing solution into the water flow.
  20. Use the bale clip provided in order to hold the trigger down.
  21. Flush the cooler with water and the solution for 2 minutes. During this flush, attach an air supply to the air valve located on the tool for 3 to 5 seconds every 15 to 20 seconds. This will create a surging action to ensure complete cleaning.
  22. Release the trigger. Rinse with water for one minute.
  23. Turn off the water valve.
  24. Attach the air supply to the air valve.
  25. Dry the system with air until no moisture is seen leaving the discharge hose.
  26. Connect the cooler feed pipe to the transmission.
  27. The cooler feed is the TOP connector at the transmission.

  28. Clip the discharge hose to the oil drain container.
  29. After filling the transmission with fluid, start the engine.
  30. Run the engine for 30 seconds to remove the residual moisture from the oil cooler.
  31. At least two quarts of the fluid should flow during the 30 second period.

  32. If the fluid flow was insufficient, check flow from the transmission by disconnecting the feed line at the cooler and observing the flow for another 30 seconds.
  33. Check for the following conditions:

    • Insufficient Flow -- Inspect the transmission for causes.
    • Sufficient Flow -- Inspect the cooler pipes, fittings and repeat the cooler flushing procedure. If the flow is still insufficient, replace the cooler.
  34. Remove the discharge hose and reconnect the cooler pipes.
  35. Adjust the fluid level.