I always think about how long it takes to get to operating temp, and, from prior experience, what temp it sits at during winter on the Hwy
My above concerns were not initially from trans temps but from engine oil temps, I had a big engine oil cooler and extended sump fitted to my my old skyline, when I was driving during one winters day after fitting the cooler the oil temp never got over 50° c, and at the track I needed to cover half of the cooler to get the oil up to 90°- 100°c, admittedly it was winter time and ambient temps were single digit
Their is a thing as to much cooling, it seems though your thermostat has it in check, apparently the operating temp for a quality trans fluid is between 80-105°c
How long does it take to get to 80°c?