Two things you can do.
1. Get a good load equalizing hitch, with a "sway" control. that has a brain, like a Reese dual cam.
2. Put a good transmission oil cooler on the truck. However, do not place it forward of the radiator, as that heat goes into the radiator.
The idea is to cool the transmission oil, "AND" keep as much heat out of the radiator that you can.
Mounting the oil cooler below the bumper and at an angle, works great, and the heat goes underneath the engine.
Andy