Every 20 degrees over 170 the life of the fluid is cut in half.

Seabass

 

Amsoil has a chart for there ATF that shows what I think is supposed to be normal or at least safe for the fluid up to 270. I know you don't want it that hot by any means but does that mean you could run 200+ for short periods with no fluid breakdown?? BTW, Amsoil uses the term "Universal" on there ATF. Is it just me or does anyone else just hate that?? (No flames there so no one get spun up, I'm planning on using it.)

 

We just pulled our 5000# 5er from Durango to Silverton Co. The tranny temp never went over 185. When I checked the level the ATF looked fine. I'm not sure if discoloration and smell are definitive characteristics of good/bad ATF but mine looked fine. I plan on changing it every year so I think I'll be all right.