Wow; Isn't that quite high gears for towing !! What does that put your towing capacity at ??
Ford 2011 brochure says F250 w 3.31 axle ratio, maximum loaded trailer weight on 5th wheels:
F250 4X4 Short bed = 15700 lbs 5th wheel towing weight
Maximum Payload weight for crew cab
GVWR 10000 lbs configuration = 2430 lbs payload (passengers, pin, fuel)
F250 4X4 Long bed crew = 15700 lbs 5th wheel towing weight
GVWR 10000 lbs configuration = 2210 lbs payload
F350's single rear wheel 4X4 are 15800 lbs trailer weight, not much difference
Payloads are quite different, 1300 lbs to 1500 lbs increase over the F250.