Originally Posted by MNRAM
I pulled a 6500# travel trailer from Minnesota to Colorado and back with my 2010 hemi quad cab and the engine oil temp ran 210 to 230, and the tranny ran 150 to 170. Generally anything under 300 degrees will not hurt a tranny. I ran in fourth gear in tow/haul mode.
Anything over 195F starts to shorten the life of the fluid though. The higher the temp, the more frequently the fluid should be changed.