Most American made petroleum based ATF has a dye in it that will start to change colors from red to brown at 275F, and go to black at 325 F
What colors is your fluid on the stick now?
If your running pure synthetic based ATF it won't start to be hurt until above 500 F
I use to see around 230 F on my 1998 1/2 Ram 2500 CTD pulling the Baker grade in August in the afternoon going to the drag strip in L.V. at 70 MPH kicked out of O.D. running the air conditioner pulling my 24 Ft Pace Shadow enclosed race trailer with the car and other goodies in it. That trailer weighed right at 9200 Lbs. disconnected from the truck on a certified CA state scale with my 3200 Lb race car in it
My trans .temp sending unit was in the front servo where the CTD registry recommends using them I had it in the bottom left front corner of the trans pan originally and I didn't see any difference in the temperature moving the sender up into the front servo port access plug hole That truck used the ATF+3 fluid in it. Around town in the summer or winter running empty it would never get above 140F no matter how hard I drove it It did have the factory towing package on it also. When ever I hooked up the race trailer to it the trans temps. went up to 180 empty or full towing on the flats
My main message is if your trans. fluid color and smell is okay your probably okay