Sounds same as on my 54 Manhattan. You can get them new from Dorman. My local O'Rilley guy found several to chose from...take one you want to match and compare. Some were "taller" than others making cotter hole line up different.
Do check threads on axle while there...clean if needed...takes a good load to pull hub down taper.
Also, I put a bit of RTV under nut/threads, as grease/oil came down the keyway and out on mine.....thought it was from seal, but not.
Bob L.