Be careful not to over-cool the fluid. In the winter, it might be good to use the radiator mounted cooler to help evaporate contaminants out of the trans fluid. The radiator-mounted cooler is downstream of the cooling fins, so the coolant gets a major temp drop before it gets to the trans fluid. I would expect the trans fluid to be somewhere around 175-200 degrees on its way back to the transmission. That should be plenty cool for all but heavy-duty towing situations.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!