reciever hitch pin. Bought a used truck with a receiver hitch. THe pin was so rusted that it was brittle. Guy who had the truck hauled a 38' powercruiser three times a year and a bass boat all the time. If the receiver came out I think the chains would have disconnected themselves. We replaced the hitch and receiver.

Thats one more thing that is on my check list every trip now. receiver, hitch and cotter pin.

Steve