^^^^^This.
I tow, on average, twice per week- about 2000# of boat/motor/trailer.
In fact, I towed my boat about 130 miles today round trip. Highway, stop and go traffic and hills.
Sport mode all the time in 4th gear is the trick. Much better towing experience when you do this!
I did some messing around with 5th gear today and watching the Scanguage. The water temperature actually dropped 2 degrees while in 4th gear compared to 5th, and the tranny temps lowered as well. I guess this is a combination of the engine not working as hard, no gear hunting/locked torque converter, and higher engine cooling fan speeds.
I also achieved 17mpg for the trip in 88 degree temps with the A/C on and that included idling in the parking lot for 15 minutes while eating a snack. Oh yeah, I have a lift, offroad tires, ,a roof rack, dual batteries and lots of supplies stored in the back...
That's pretty darn impressive I say.