Transmission Cooler # D13504 Routing Recommendation for a 2010 GMC Sierra 1500 4.8

Question:

I have 2010 GMC sierra 1500 4.8 v8. I have a factory cooler I am trying to install d13504 in series with the factory cooler. The cooler lines from the trans. go through the radiator first and I canot determaine the derection of the trans. fluid. Does it go into rad.first or after coolers.

asked by: Darryl N

Expert Reply:

You will want to install the Derale Series 8000 Plate-Fin Transmission Cooler Kit w/Barb Inlets - Class IV - Efficient, part # D13504, after the factory cooler.

If you were to put the # D13504 before the factory cooler, you would actually be cooling the fluid and then reheating it once it went through factory cooler, making the # D13504 completely useless.

The method for determining which line is the return line is to:
1. Start engine while engine is cold
2. Put your transmission into Drive for no more than 10 seconds
3. Stop engine, remove keys
4. Identify oil return line by feeling both lines, the cooler of the two is the return line and the line you should install your # D13504 in that line.

I have included a link to an FAQ on transmission coolers below, as well as a video of a transmission cooler being installed on a similar vehicle.

expert reply by: Jameson C