[sick472]

The path should be from the tranny to the radiator then to the cooler and back to the tranny.

The tranny cooler should be in front of the radiator (if that's not obvious). This means it will likely be the most efficient in cooling the fluid. So the radiator drops it potentially down to the coolant temp then the tranny cooler takes it down even further.

AND make sure your temp gage sensor is in the tranny pan or at least in the tranny fluid line that carries the fluid from the tranny to the radiator.