That's what I meant... heh not cotter pin.
I guess Triki got it.
Weird it has that "slot" in it... must be for locking it in place...
Which...
Obviously did not work due to it being "lost". heh
Not a Lynch Pin, because the OP says it swings freely.
BCH, most of the lynch pins now days are flat on one side of the pin part. Just bought some at Tractor Supply a couple of days ago. Sorry I can't post a photo.