09 F150 downshifting

Mrbillsa wrote:
I'm getting ready to pickup our new travel trailer next week. I have a FX4 with supercab, tow package, 5.4 V8. I put new tires on Goodyear dealer put G load rating on, might be overkill. I put aftermarket power fold tow mirrors on, and most recently a fiberglass topper. There's not a lot of extra weight on it, since I had a hard cover on it before topper. I've noticed the truck downshifting quite a bit, even when I touch the gas going downhill. Not sure if this is normal and just resign myself to driving in tow mode or what. I know the mirrors are catching a lot more air than the stock ones. Thanks in advance for input.

That thing is going to ride like a buckboard. If the tires are larger than stock, that will cause more downshifts and less power. Wind resistance causes a large amount of power consumption, all you can do is drive slower. Yes, use tow mode whenever the trailer is attached, it will be better for the transmission, help in slowing (some models), and may help in cooling.