My hitch has developed some play at the point where it is pinned to the bed rails. It clunks when you stop and clunks when accelerating. Not bad, but enough to bother someone as anal as me. It seem...
I know this sounds crazy but each time my hitch would start clunking I would grease the hitch plate with a teflon hitch lube or wheel bearing grease.
The clunk would stop. An old timer 5th wheel RV'er suggested I try it. He said the grease acts like a shock absorber due to the hydro static properties of the grease under compression.