I am not talking about anything legal as far as what the sticker saids the truck will haul. Buy you can buy a set of hellwig progressive helper springs for the rear. I have a 2001 F250 extended cab with a 8ft bed.It has the 7.3 diesel with a 3:73 rear end. The only difference between it and a 1ton single wheel truck is the springs. I have a 25k airsafe air hitch you have to have a forklift to put it in the bed. I have a 37 gallon fuel tank in front of the tailgate. I have a generator between the air hitch and the front of the bed. I have a 2006 Carriage 5th wheel that fully loaded and weighed on a scale. Weighs a little over 14,700lbs. Of that is a little over 3,100lbs hitch weight. So their is 11,600lbs on the tires. When I am hitched and you look at my truck from the side. It is still not level. It is just a fraction above level at the back. The truck has no problem pulling my 5th wheel . It has been pulling it now for 14 years. I am not saying the truck is legal. But you can fix your truck to do the job if you want to.