Mine is under the bed on a heavy duty frame hooked the frame rails. Very similer to a battery holder. It hanges out away from the frame about 3", at a slight angle to pick up air. The exhaust is on the drivers side of the driveshaft so the cooler is all by itself.
I am only running a stock 250 and turbo 350 trans, so heat is not really an issue. After 6 years and 7000 miles, the fluid still looks brand new. Heavy loads and high horsepower create lots of heat, its not that big of deal with stock equipment. Remember the air cooled powerglides? Joe