We have been having this problem with our new camper...the trailer does not want to come off the TV ball. We have been using the rocking method...I move the truck back an inch, forward an inch, while Tom works on the hitch until he gets it uncoupled.
Unfortunately we kind of panicked at first and drove around town with the camper hooked up for a day and a half!!!
Seriously though, we have 2 5/16 ball as that is what the dealer told us we needed. I read this thread and see it is written on the hitch?
However, I didn't see that tonight when we were cleaning the camper and it is parked at a friend's lot tonight in preparation for her big wash and wax next weekend.
Someone mentioned that it might be a tight squeeze because of the paint on the new camper hitch? Anyone have this happen before? And yes, we did grease the ball.