5.4L 2003 F250 Crew Cap Towing Capacity

As Old Biscuit was alluding to, mfg's "tow ratings" should not be a factor as you will run out of payload capacity long before you come close to their tow rating. Find your payload capacity on your door jamb and use that for figuring out what you can to. Typically, that labeled payload capacity includes a full tank of gas plus a 150 lb driver. Any thing else you put on the back of the truck.... you (anything over 150 lbs), passengers, equipment, tools, camping gear hitch, trailer pin/tongue weight...etc will be counted towards that limit. If you don't know the trailers pin/tongue weight, you can usually figure 12% for tongue trailers and 20% for 5th wheels.

Hope this helps

Ron