Diesel Data: Automotive Repair

Transmission Fluid Cooler - Backflushing and Cleaning

Transmission Fluid Cooler - Backflushing and Cleaning

CAUTION: Whenever a transmission has been disassembled to install new parts or a new or remanufactured transmission has been installed, a new transmission fluid cooler (either in-tank, auxiliary or OTA) if equipped, will need to be installed. Using a suitable torque converter/fluid cooler cleaner, clean and backflush the transmission fluid cooler tubes.

CAUTION: Use only clean automatic transmission fluid specified for this transmission. Do not use supplemental fluid additives, treatments or cleaning agent. The use of these materials may affect transmission operation and result in internal damage to the transmission.

CAUTION: When internal wear or damage has occurred in the transmission, metal particles, clutch plate material, or band material may have been carried into the transmission fluid cooler. These contaminants are a major cause of recurring transmission concerns and must be removed from the system before the transmission is put back into use.

1. Carry out backflushing with a suitable torque converter/transmission fluid cooler cleaner. Test the equipment to make sure that a vigorous fluid flow is present before proceeding. Install a new system filter if flow is weak or contaminated.





2. If equipped, remove and discard the transmission fluid in-line filter.
3. To aid in attaching the cleaner to the transmission steel cooler lines, connect two additional rubber hoses to the transmission end of the steel transmission cooler lines as described.
^ Connect the cleaner tank pressure line to the steel transmission cooler return line (longest line).
^ Connect a tank return hose to the steel transmission cooler pressure line (shorter line). Place the outlet end of this hose in the solvent tank reservoir.
4. Turn on pump and allow the clean transmission fluid to circulate a minimum of 5 minutes (cycling switch on and off will help dislodge contaminants in cooler system).
5. Switch off the pump and disconnect the pressure hose from the transmission cooler return line.
6. Use compressed air to blow out the cooler(s) and lines (blow air into the transmission cooler return line) until all fluid is removed.
7. Remove the rubber return hose from the remaining steel cooler line.