My 2006 ram 3500 single wheel 4x4 long bed gets around 20 MPG out on the road empty, it will get 14 MPG pulling my 24 ft. Pace Shadow weighing 8600 lbs on the axles, it will avaerge bewteen 14 and 16 MPG empty in town with some short highway driving. I own a 36 Ft fifth wheel travel trailer with three slide outs, it weighs 11,800 on the two trailer axles and puts around 1500 lbs more on the truck, some on the front axle but most of it on the rear axle. The truck rides and feels better pulling the fifth wheel than it does pulling the car trailer The best mileage I got towing the fifth wheel from central Oregon to central Arkansas three years ago was right at 12 MPG, the worst mileage was from the eastern border of Okolhoma(SP?) on I 40 to the middle of the Texas panhandle into a direct head wind, it got a little above 8 MPG on that run at 65 to 70 MPH I had a 1998 1/2 24 valve automatic short wheel base 3/4 ton extended cab two wheel drive, it got excellent mileage until Mopar did a "emissions " recall to reflash the computer, it sucked after that I ended up having a freind, who worked at Cummins Pacific, install a industrial 230 HP program into my onboard computer, that made it better but not as good as it was originally BTW, I owned three different car hauling trucks before switching to the CTD, 1973 1 ton crew cab Ford 390 with a C6 and 4.10 gears , 1957 1 ton Dodge with a 318 and a four speed, 4.10 gears and the first one was a 1955 Dodge 1 1/2 ton with a four speed and a two speed rear end with 9.50x20 inch tires, it orignally had a 254 C.I. Dodge 6 cylinder flathead truck motor in it and later I put a 1957 392 New Yorher passenger car hemi motor in it. None of the gas trucks ever got more than 10 MPG going to and from the races, never