How To Find Return Transmission Line When Installing Derale Series 8000 Transmission Cooler

Question:

Is the hot transmission line coming out of the transmission the upper or lower on transmission

asked by: Kevin C

Expert Reply:

In regards to installing a transmission cooler like the Derale Series 8000 Plate-Fin Transmission Cooler Kit part # D13502, you will need to identify both the factory hot and cold (return) transmission cooler lines. In order to do this we recommend driving around the block a few times then getting under the vehicle and grabbing both lines going to and from the transmission, one should be noticeably cooler than the other and that's your return, the one you'll need to use. The lines/fittings might also be labeled as return and that's the one we need. There's also the option of using a Powerbuilt Infrared Engine Thermometer part # ALL648564.

Unfortunately, the position of the cooler lines on the radiator/transmission won't tell us which is the return as it can be different from vehicle to vehicle.

expert reply by: Conner L