Trans temperature gauge

bmanning - I'm not disagreeing with you. My primary point was to recommend against trying to run trans fluid at too low of a temperature as it is not necessary. If you run too cool you never boil off any condensation that has collected inside the trans. Most, if not all, trans cooler sellers want you to mount their cooler after the vehicle radiator. Looking, I suppose, to get the most cooling of the fluid and thus make their cooler look the most effective or to mitigate other cooling system problems that should have been addressed first. I agree with you that modern fluids can operate successfully at higher temperatures than in the past. The '91 Class A I had previously would easily generate temps above 250* on long uphill runs and benefitted greatly from a quality plate trans cooler.