We've been having trouble with our MorRyde pin box too. When it arrived, we installed and went on a 142 mile trip down to VA and then back. GREAT ride! We were very happy we got it BEFORE we went to Goshen. Helped smooth out the rough roads on the way to IN. By the second day on the ride back home, EVERY time we stopped and started, the pin box was slamming metal on metal. You can see the dig marks on the bottom plate where the top is hitting (or vice-versa).
Called MorRyde and they thought we might have had the wrong spring, we verified that it was the #4 ( we weighed 12,656 at the rally). MorRyde sent us a replacement spring which we installed. We've only taken about a 5-mile trip since the replacement spring was installed, and are still not happy with the way the pinbox is handling. We have some play now in our hitch (Curt E-5 slider) - not sure if that is contributing to the problem or not. MorRyde said to put a piece of tape on the frame of the pinbox to see if it is still hitting. We have less travel now than we did before on the discs.
Will have to wait till Aug 9 to test it on the next trip out.
Karen