[twindman]

Pullrite is VERY good helping out. Also, your pin box doesn't look like you have the special plate on it required for the slider. At least mine is that way. It has a little V shaped plate/ridge the fits into the truck portion so when you turn it forces the slider to move back. I have towed over 100,000 miles with a pullrite and have had no problem wtih this roller coming off. My guess is it wasn't properly tighted from the factory and eventually fell off.