I was putting my trailer on the truck yesterday and the part inside the coupler that holds the coupler on the ball got caught on top of the ball. It looks fine but something seems to be wrong with it now . It will hold the ball fine, but when I unhook the trailer I have to get a screw driver and pry the little plate back out so I have hook up the ball again. Any ideas on how to fix it?? I took the whole assembly out today and put it back in again but still the same problem. The spring inside is not broken and all parts appear fine, just seems like the plate inside won't move freely.