I was going to ask the same question about trany temp. I just made a 100 mile run and my temp was 170-172. This past summer pulling my RV it ran 195-202 in 90 degree ambient up and down grades in western Montana. I changed my fluid at 15000 miles---the book says 150,000----I will change again before summer at 42-45,000 miles.
Anybody---am I wasting my $$$$ by changing the expensive trany fluid that often????