A good friend with a 77 Airstream sent me a text tonight that when he unhitched this piece of metal fell out of the coupler. Having not worked on this era I don’t know. He said the arm that locks in below the ball is solid and latched in he can lift the truck with the tongue jack so it’s staying latched. What else could it be? Is it possibly just debris that got stuck in grease at some point, or is there some type of inner surface at the top of the receiver he couldn’t get to perhaps?
Thanks for any thoughts I can pass on. He’s out camping and didn’t have much for resources.