Does anyone know what this is? When I had to remove my fuel tank, this was inside one of the frame rails. I am not sure if it came loose. I didn't see the other end. It may have been trapped there...
That part appears to be the stock body bushing that comes installed on a Ford chassis. Most RV manufacturers do not use those and weld directly to the frame rails in place of the rubber bumpers. I worked for a manufacturer for many years and those rubber bushing would be laying around the chassis weld shop where they were suppose to be put in the trash. I am sure it just got dropped down in the frame rail by the tank and has rattled there until you found it.