I get a steady 203-204 pulling my 3000 pound boat on a 95 degree day at 65mph.

How about you? What are you towing at what temperature?

 

I'm usually a bit hotter 210-215 pulling the large sail behind me

 

What are you towing Mike? Travel trailer? Weight?

 

203-210 depending on whether I am on flat ground or pulling a 7% grade. 5500 lb travel trailer in Utah usually pulling at 70 mph.

 

It's a travel trailer. 8' wide, 10' tall not including the AC unit. The GVWR is 7700Lbs but that's a worthless number unless you bring 3 of everything and a spare kitchen sink. It's true weight is 6600lbs ready to go for a week trip.

 

I tow a 30' travel trailer, around 6900 pounds loaded. Truck is a 2019, 2.7, 3.73 gears, 4wd, and I tow 60-65 mph with Tow/Haul engaged(10,9 gear locked out) and it stays at about 201-202'. May go up 3-4 degrees on hills but comes back down.

 

what happens if you engage 10th gear on level ground at the 65mph speed?? Have you done anything to your cooling system like change the thermostat?
How many miles on the transmission fluid?

 

I have never tried it in 9th or 10th. Those seem like way too steep of overdrive gears to tow such a big wind resistant load. Only 38,000 miles on truck so all is the same as when new.

 

Fellow 2.7 3.73 owner here with a 7000lbs wet travel trailer and tow/haul mode will select 9th but not select 10th at speeds up to 72mph. After 72mph the RPM is high enough to go to 10th. If I disengage tow/haul mode and use normal then the truck will select 10th gear as long as it can maintain speed. If speed begins to slip then the gear will drop. In general you can't pull in 10th gear at 65-70 unless you are slight downhill or have some tailwind. Like the OP I lock out 10th and 9th and tow almost exclusively in 8th gear, which is around 2200-2400 RPM when going 65-70. This is a really nice sweet spot where engine noise is still minimal and there is a lot of reserve power for light hill climbs without having to ever drop a gear.

 

205*F was my norm during the last trip. 10’ tall, 7’ wide TT. About 3800#. Forgot to engage tow/haul a lot. Especially the whole trip home.