New truck-bed to high for fiver hitch-advice please

I had the same problem with the 2014 Chevy 3500 Crew cab I purchased. What I did was loosen the pin box and lowered the pin 1 hole on pinbox. That was about 2 1/2" and let my pinbox clear the side rails when turning. By lowering the pin it raised the nose of the 5er. I probably could have gotten a different pin box but this was free rather than spending the high $$ for a new pinbox. Good Luck and Hope this works for you.