I wasn't going to respond because you specifically stated new trucks, yet no one responding mentioned what year their TV is. We used to have a '99 F250 6.8L V10, modified, including the RAR modified from 3.? (can't remember) to 4.3. It did OK (translates to kept up but struggled a little on grades) towing an 11k TT. Then we bought our current fifth wheel. After dropping to 7 mpg towing from 10, and having a butt puckering ride up and down mountains, we upgraded to an '11 F350 6.7L Diesel DRW and have never looked back. Not only do we average 12mpg towing, but the towing power is amazing. Don't get me wrong, we don't tow fast flat ground or up and down hills, but the power is amazing towing over the mountains that we do and to have the power to hold us back when needed is worth every penny of that purchase.