Hi I have a 2001 f-550 that is a 7.3 diesel and 4x4 with 4:88 axel, six speed manual trans. truck has 285000 mi. Bought the truck new and use it daily in my landscape bussiness to haul up to 5 ton loads.The ride quality is rough when empty but much better with 3 ton or more on board.fuel milage never goes below 10 and very rarely above 11.does not seem to matter loaded or not.The interior noise level is somewhat louder than my 2005 dodge 3500 with my alaskan camper and a much better ride quality. Do not know if this a good comparison with the newer trucks. hope this helps
Ramp