Transmission Fluid Cooler - Backflushing and Cleaning

Transmission Fluid Cooler - Backflushing and Cleaning

CAUTION: Whenever a transmission has been disassembled to install new parts, or because the valve body sticks from foreign material, the transmission fluid cooler must be cleaned using a suitable torque converter/fluid cooler cleaner. Under no circumstances should torque converters be cleaned by hand agitation with solvent.

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 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 service.





1. If the vehicle is equipped with an in-line transmission fluid filter, remove and discard the filter.
2. 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.
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 solvent pump and allow the solvent to circulate a minimum of 5 minutes (cycling switch on and off will help dislodge contaminants in cooler system).
5. Switch off the solvent pump and disconnect the solvent 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 solvent is removed.
7. Remove the rubber return hose from the remaining steel cooler line.





8. NOTE: If the vehicle was not equipped with a fluid filter, install a fluid filter kit and follow the instructions supplied in the kit. If the vehicle was equipped with a fluid filter, install a new filter.

Install a new in-line transmission fluid filter kit or filter.