Don't know if you have 2500 or 3500 so look it up HERE
Have you weighed your truck ...........if so you will find out that you will run out of truck GVWR, RAWR and maybe Rear Tire Load Rating LONG before reaching that mfg. magical tow number(s)
Weigh your truck....then you will have real information to base tow decisions on VS mfg. published (manipulated) figures