WD40 did the trick!

reminds me of the old Jamaican Chinese guy I met at Canadian Tire "man WD40 good fuh one hundred and twenty ting icluding artaritis" 

that is an expensive piece of equipment. You may not have tighten the hex screws down fully if you are using the adapter for the 2 inch hitch receiver. They could possibly get stuck. There is nothing to hold it except if you tighten the lock nut so you cannot unscrew it. The stinger clicks in when  installed right. My wife had that on her truck. I am sure with some jiggling you will get it off.

that is exactly what it was, once I got it off I noticed that and fixed it. Goes on and off the hitch beautifully now. Thanks.

It is a really nice rack indeed. 

Speaking of nice racks, you shoulda seen where

i went cycling today, racks galore.

I've never used any contraption on my car, I either ride from start to finish or break down my bike. I treat my bike like my woman, it stays in my car not on the roof or trunk. My Grandad would be appalled by that, hehe.