A/T Oil Cooler Flushing and Flow Test

Notice: You must flush the cooler whenever you remove a transmission for service. Cooler flushing is essential for transmission replacement, major overhaul, whenever you replace a pump or torque converter, or whenever you suspect that the fluid has been contaminated. Use J 35944 to flush the cooler.

After filling the transmission with fluid, start the engine and run for 30 seconds. This will remove any residual moisture from the oil cooler. A minimum of two quarts of fluid should flow during a 30-second period.


Checking Fluid Flow:

Caution: Transaxle oil is hot and may cause injury. When the cooler hoses are disconnected, place the ends of the hoses in containers to catch the oil.

Disconnect the return transmission fluid cooler return line at the transmission (upper hose) and perform the following:
- If the flow from the cooler return line to the transmission is insufficient, disconnect the transmission oil cooler feed hose at the radiator (upper hose) and observe the fluid flow. If the flow from the feed hose is sufficient, repeat the cooler flushing procedure. If the flow from the return line is still insufficient, blockage exists in the cooler. Replace the radiator.
- If the flow from the transmission feed hose is insufficient, and the flow from the cooler return line is sufficient, the transmission is the cause of the flow problem.