I had one of mine in trans pan and then in the front servo like the Cummins Tubo Deisel Network recommends for the Dodge Cummins powered trucks, I didn't see any real differences in the temps. The hot fluids coming out of the front of the trans to the cooler is not what the trans. pumps through the trans. It pumps and operates on the cooler fluids returning into the pan from the rear cooler return line