Transmission Cooler Installation Tips for a 2007 Toyota Tacoma

Expert Reply:

Orientation of the inlet and outlet ports does not matter, and it does not matter which line goes where. Your best bet is to figure out the best mounting situation for the easiest connection to your vehicles transmission fluid return line. If you can mount the cooler with the inlet and outlet ports up you will get slightly better cooling performance, but testing has shown that there is only a difference of 2 or 3 degrees from any other position.

Transmission coolers are straight flow through devices so direction of flow does not need to be considered, either port can be used as inlet or outlet.

Normally, the lower line coming out of the OEM radiator tank mounted cooler is the return line. Check first to be sure though. With the engine cold, start the engine and let it run for 10 seconds while shifted into drive. Then, put it back into park, shut the engine off and remove the keys. Now, feel both transmission lines, the cooler line of the two will be the return line.

If you have metal transmission lines, the easiest method for installation of the cooler would be to measure the outer diameter of the return line and use compression fittings, like part # D13032 to attach the hoses. Most transmission lines are 3/8 inch O.D. but you should measure to be sure. To install the compression fittings you will need a tubing cutter, like part # BTMTC58 and two compression fittings properly sized to fit on the cut ends.

We have a very informative video that shows this type of installation that should be helpful. I also added a photo showing the best cooler location and a typical compression fitting installation drawing.

expert reply by: Bob G