You will be limited by the GCWR/tow rating for any bumper pull/TT. That's in the 9500 pound range for 3.73 axle and 14k pound range for 4.10.
For 5th wheel, it gets messier. You will probably be limited at 9500-ish pounds again for 3.73, but payload limited for 4.10 axle.
You can determine the axle ratio from the factory by locating the sticker in the glove bow listing all the RPO codes. It will have one of the following: GT4 = 3.73 and GT5 = 4.10.
Payload will be indicated by the Tire and Loadign sticker on the driver's door or door jam. It looks like this: Note what your truck has where mine says 2051.
