This is what I see NOT towing just daily driving...

 

This time of year I see 190* just driving as a DD but it depends on the outside temp to some extent as well. During the summer months towing my boat or TT, it goes up to 200 or 205, but that's it.

 

Please provide details of your truck. Year, engine, etc.

The 6R80 and 10R80 both have a thermostat that keeps the fluid at 190-195 minimum. Hitting 205 isn’t unusual with the right conditions even without a trailer attached. Everything up to 245f is considered normal before the truck will start cutting power. I’ve hit 235f towing on a long winding uphill without issue.

 

In the 4 years I've owned mine the temp has been between 195 and 205 virtually all the time. Towing or not, but I don't currently tow over about 3K. In hot weather I've seen 206-207 after a steep climb.

 

2018 f150 xlt 5.0 v8 7000 gvwr4x4 Supercrew 145" wheelbase 3.55 axle 18" wheels
Pro Trailer tow package with sway and brake control

 

I never had a temperature ever pop up my first two years of driving my 2017 Lariat w/ 3.5EB. Last summer while towing our toy hauler with a total weight at the time of 7,700# I started seeing it pop up on inclines. As soon as I started back down it would drop. It only showed the temp when I got above 225 degrees, and the highest I got was 238. I was a bit concerned for awhile but beginning to think that is within reason. Any thoughts?

 

I once hauled 15k up a long and very steep grade with my 2500hd. Trans got to 238 degrees. These new fluids have a limit of 260, but I personally wouldnt push it over 235. Only reason I let it get to 238 was we were almost to the top. And that was in the summer.
I suspect these 10R80's are equally as capable of handing what that older GM trans could handle. If not more. But I believe the truck goes into limp mode by then.

 

This. It drives me crazy when people start threads asking about aftermarket transmission coolers because they are seeing temps around 195. The truck actually works to get the transmission over 190, it's where its designed to operate.

My truck must be an oddball, I drive about 50 miles round trip highway to and from work. Set the cruise at 80 and by the time I get home the transmission is at 205. I have noticed if I slow to down to 70 or so the temps hover closer to 200. With out ~6,750lb boat we see nothing over 210 and thats only after climbing a pretty large hill to get out of the marina.

 

Mines somewhere around 205 or so 99% of the time unloaded. Towing a travel trailer I always see 220-240 up the grades. 210ish on the flats towing around 65.

 

In the summer time with my 2019 5.0 XLT SCREW, I regularly see transmission temps up to 206, and that's with no trailer or weight in the truck and driving on flat-ish roads. When the outside temp drops, the transmission temp drops down into the high 180s or 190s.