Former Wrangler and Bronco driver here with about 8 years of driving with a hitch rack on them. What you need are these:

Anti-Rattle Hitch Lock for Kuat Transfer Bike Racks - 1-1/4" and 2" Hitches Kuat Trailer Hitch Lock HLT

Kuat Hi-Lo Hitch Extender - 2" Hitches - 7" or 10" Extension - 2-1/8" Rise/Drop Kuat Accessories and Parts HL20B

The threaded bolt with lock is used to attach the extender to the trailer hitch. Then connect the extender to the rack with a locking pin, and tighten up the expander. Should be rock solid.

Just leave the extender on the truck when no in use. I just took the rack off. If you do that, watch your shins when accessing the cargo area.