the company has a '04 peterbilt with the 8.3, this is a tandem axle dump, weighs 22,000lbs empty and fully loaded its 50 to 55,000, the truck runs in the mountains between 5000 and 7500ft elevation, mileage empty is 9, loaded its 8, power is adequate, for the load, but its definitely not a big cam 400, [ it doesn't get 4 mpg either] it has a 8LL transmission and is about like driving one of the old 290 trucks, not bad, considering the difference in fuel mileage made the truck payments when it was new, the truck will run 80 mph all day long loaded, on the flats, drops to 55 when i pull a mountain pass with a 6% grade takes 2 sometimes 3 downshifts at full loaded weights,the pass road is 11 miles long if this truck was a rv toter mileage would be up considerable and it would just be loafing power wise, my personal truck has a first gen 5.9, great power and mileage for a 1 ton pickup, but its making about half the power the 8.3 is, i mean there is a big difference! both truck are going strong bumping on 300,000 miles, take care of it and a million miles between overhauls is defiantly possible, not to mention you would have enough truck to handle the load, unlike a pickup, as for general driving experience , the pete drives and handles just like a oversize pickup, and its pretty quiet and tight inside running down the road, tilt and telescoping steering wheel good stereo, air ride seat ect, and this pete has a Chalmers suspension, one of the hardest riding ones out there, and even empty its not bad, if that freightliner is sitting on a air ride suspension, you'll think you have a luxury car