Transmission Fluid Cooler Backflushing and Cleaning

Transmission Fluid Cooler Backflushing and Cleaning









Transmission Cooling Fluid Flow









NOTICE: Whenever the transmission has been serviced or a remanufactured transmission has been installed, the transmission fluid cooler tubes must be cleaned and backflushed to remove any contaminants or transmission failure will occur.

NOTE: Transmission fluid cooler backflushing and cleaning will be performed using the Transmission Heated Cooler Line Flusher or equivalent. Follow the manufacturer's instructions included with the machine. Test the equipment to make sure that a vigorous fluid flow is present before proceeding.

NOTE: Install a new auxiliary transmission fluid cooler as part of a transmission overhaul, or when installing a remanufactured transmission.

NOTE: Repeat repairs will occur if the transmission fluid flow does not meet specification. To avoid repeat repairs, carry out the Transmission Fluid Cooler Flow Test. For additional information, refer to Transmission Fluid Cooler TorqShift.

NOTE: Carry out this procedure with the auxiliary transmission fluid cooler and the transmission removed from the vehicle.

1. If equipped, remove the transmission fluid in-line filter. Install a straight pipe with hose clamps in its place.





2. NOTE: The transmission cooler return tube can be identified as the tube that runs from the auxiliary transmission fluid cooler outlet (driver side) to the rear of the transmission.

Flush the transmission cooler return tube as follows:

1. Using the appropriate fittings, connect the cooler line flusher pressure and return lines to each end of the transmission cooler return tube.

2. Switch the cooler line flusher pump on and allow it to run for 60 seconds.

3. Turn the switch off after 60 seconds and disconnect the pressure line.

4. Blow air through the cooler tube until transmission fluid has drained back into the cooler line flusher.

5. Disconnect the cooler line flusher return line.

3. Flush the transmission cooler pressure tube and radiator in-tank cooler as follows:

1. The pressure tube and radiator in-tank cooler must be backflushed, then forward flushed. This is necessary to thoroughly flush the in-tank cooler.

2. The transmission cooler pressure tube can be identified as the tube that runs from the auxiliary transmission fluid cooler inlet to the front of the transmission.

3. Using the appropriate fittings, connect the cooler line flusher pressure line to the radiator in-tank cooler outlet. Connect the cooler line flusher return line to the transmission cooler pressure tube (the cooler tube near the transmission bellhousing).

4. Switch the cooler line flusher on and allow it to run for 15 minutes.

5. Turn the switch off after 15 minutes then reverse the cooler line flusher lines.

6. Switch the cooler line flusher pump on and allow it to run for 15 minutes.

7. Disconnect the cooler line flusher pressure line and blow air through the line until the transmission fluid has drained back into the cooler line flusher.

8. Disconnect the cooler line flusher return line.

4. Install a new transmission fluid in-line filter if equipped. Install the transmission fluid in-line filter kit if the vehicle was not equipped with the kit. For additional information, refer to Transmission Fluid In-Line Filter Transmission Fluid In-Line Filter.