Wouldn't even tow in O/D? Why do people insist on towing in O/D? I use O/D for empty cruising mileage and let the transmission decide while towing. Direct drive is the preferred selection for towing heavy with the gas engine. We towed our 8500 lb mid profile 5th wheel 1250 miles four days after I bought it for our Christmas vacation. I set cruise on 60mph on the way out as it only had 240~ miles on it. On the flats, it's held O/D at 1900~rpm. In rolling hills, it shifted to direct to run 2700~rpm. On two longer steeper hills, it shifted to 3rd to run 3800rpm. 3800rpm is peak torque rpm, the bottom of it's power band. On the way back with closer to 1k miles on it, we ran 65mph on much of the trip with no trouble. 2000rpm in O/D, 2800rpm in direct up rolling hills or against headwinds and an occasional 4200rpm in 3rd with plenty of power. Why some consider the 5.4L running in it's normal operating rpm range and not even getting close it peak horsepower rpm a problem is beyond me. I ran my previous Hemi powered 2500HD the same way and at 120k it still ran like a new engine. I've never known it to be harmful to run an engine in it's normal operating rpm range and power band. I expect the 5.4L to last a long time with proper care and normal operation.
That is unless I trade it for the 6.2L...
Why don't diesels tow 1000rpm below their peak torque rpm? 2000rpm is but a blur. You can't pedal that fast or count that fast or even see that fast. It is NOT low rpm. But it is the normal operating rpm for the small pickup truck sized diesels with an occasional downshift to run 2800~rpm up the steep ones while towing heavy. Won't hurt it either. We did it many times with our Cummins Rams.
OTR trucks run 1100~rpm with an occasional 1800rpm climb. Pickup truck diesels run 2000~rpm with an occasional 2800~rpm for the climb and the gassers run 2000-3000rpm towing with an occasional 4000~rpm for the climb. It's all normal operation and not an indication by any means that any of them are struggling or "screaming".
I need to stay away from the Ford dealerships when the 6.2L starts showing up!