You need to upgrade that factory 2" receiver. I have broke the one on my 04 F-250 with the same ratings. Get a Titan 2.5" unit. They are rated at something like 15,000# and 17,000# WD.
The other big issue with 2" receivers is the hardware that you get to go with them. Most is rated at 10,000# or less with few exceptions but if you step up to the real stuff, 2.5", you can get bars and balls rated at 25,000#.
By the way its not just me who has broken the hitch. My uncle did also and I know of a few other guys who have doing heavy bumper pulling. These were not old rusted out hitches either, 2 years old or less on both me and my uncles.
Chris