I have always been annoyed at the clanking and banging of my anderson rail mount 5th wheel hitch. There is just enough play, where the hitch pins into the rails, that it creates this clanking. Curt hitches sells a silencer kit
http://www.curtmfg.com/part/16900. I tried the silencers but they were to thick, when mounting the hitch to the rails the pins would not go in. So I continued using the hitch and enduring the noise. One day I was sitting in the garage and looked up at an inner tube hanging on my mountain bike. I light went off. I cut 4 pieces of inner tube to the same shape as the Curt silencers. Installed the hitch, pins went in fine. When we towed, success no more clanking or banging. The towing experience improved dramatically.