There is a whole lot of similar threads on here. If you have the factory installed lippert 1.25" bolt on receiver on your rig....it is very weak. That receiver allows a lot of flex, so the load can really get to bouncing, and that is where the real issue lies. If you feel you want to put a hitch on the back of the fiver, I suggest you have one custom welded on that is more substantial. I ended up putting a 2" curt receiver on the front of my truck for the bikes, and that has been idiot proof.
Plus the fine print on every bike rack I had..states if used on the back of an RV, the warranty is void.