GM Service Manual Online
For 1990-2009 cars only

In a major transmission failure where particles of metal or engine coolant has been carried with the fluid throughout the transmission and its fluid cooling system, it will be necessary to flush out the fluid cooler and its connecting hoses. To flush out the fluid cooler and the hoses use the following procedure:

  1. Raise the vehicle. Support the vehicle. Refer to Lifting and Jacking the Vehicle in General Information.

  2. Object Number: 166193  Size: SH
  3. Disconnect both of the cooler hoses (1,2) at the clamps (3) on the right side of the transmission (4).
  4. Place a hose over the end of the fluid cooler inlet hose from the left side of the transmission fluid cooler.
  5. Insert the hose into an empty container.
  6. Using a fluid suction gun, flush clean solvent, or the equivalent, through the return hose from the right side of the transmission fluid cooler. Flush until the clean solvent comes through the hose attached to the inlet hose. This process will back flush the transmission fluid cooler.
  7. Remove the hose from the cooler inlet hose.
  8. Place the hose on the return hose.
  9. Insert the hose into an empty container.
  10. Flush the clean solvent or the equivalent through the inlet hose until clean solvent comes out of the return hose.
  11. Apply compressed air to the return hose in order to remove the remaining solvent from the fluid cooler.
  12. Flush the fluid cooler with transmission fluid.
  13. Reconnect the fluid cooler hoses to the cooler lines at the right side of the transmission.