The coupler that SMB used is not well designed or robust. And, to top it off, the coupler is rated at 2000# while the trailer is rated at 2500#.
I changed mine to the AT Max Coupler:
This coupler has polyurethane bushings, zerk fittings, etc. It is well designed, well made and rated for 6000#.
I found it fit better for me if I mounted the round, rotating part in the van hitch and the U-shaped piece on the trailer tongue
I made a plastic plug to fill the hole in the end of the trailer tongue.