mcsandmanExplorerJul 27, 20142015 F250 super cab, 6.7 diesel w/3.31 locking axle(Truck payload: 2,970 max. lbs ; towing capability: 16,300 max. lbs) What kind of mileage can a guy expect when towing 9,500 GVWR trailer? and mileage when not towing anything?