A bit late to the game with an apples to oranges i had. My old 2011 Ram 1500 outdoorsman with 3.92 gears an the 5.7L. While altitude was never much of an issue on the flat prairies but I did tow heavy quite often.
The only time I managed to get the transmission temp up to 225F was with a very heavy head wind while trying to maintain 100 to 110km/h. That 545RFE was out of gears and in between gears for over 100km. The coolant was fine though. Although I had 12,000 pounds of hay stacked up very high.
Some other times I could get the coolant to 225F and the oil to 240F was towing 14,000 pounds up a steep grade for a mile. The transmission temp was fine as it held a gear and kept the revs sky high. I could not muster anything above 60km/h by the top.
Other than playing half ton hero, that truck never batted an eye with any other load.
Now my work truck, which is a 2018 F150 5L with the 10 speed. Haven't towed very much with it but I was doing some offloading at work today. Had to follow some goat trails that were pretty steep. Held it in 1st gear and needed 4x4 to traverse a bunch of it. The fans kicked on high and I managed 246F transmission temperature after just a couple miles bombing around. That really surprised me as I have never hit those temps in similar conditions with other makes.
The only time I managed to get the transmission temp up to 225F was with a very heavy head wind while trying to maintain 100 to 110km/h. That 545RFE was out of gears and in between gears for over 100km. The coolant was fine though. Although I had 12,000 pounds of hay stacked up very high.
Some other times I could get the coolant to 225F and the oil to 240F was towing 14,000 pounds up a steep grade for a mile. The transmission temp was fine as it held a gear and kept the revs sky high. I could not muster anything above 60km/h by the top.
Other than playing half ton hero, that truck never batted an eye with any other load.
Now my work truck, which is a 2018 F150 5L with the 10 speed. Haven't towed very much with it but I was doing some offloading at work today. Had to follow some goat trails that were pretty steep. Held it in 1st gear and needed 4x4 to traverse a bunch of it. The fans kicked on high and I managed 246F transmission temperature after just a couple miles bombing around. That really surprised me as I have never hit those temps in similar conditions with other makes.