My 57 has acquired a new problem. When shifting into and out of third gear, there is a slight grind for a small portion of the lever travel. It is no where near as bad as the grinding is if you try to shift into unsynchronized first at a reasonable speed (over 5 mph lol).
I assume the tranny is the original, however it could be the original mate to the 65ish 283.
What could be wearing out and causing this? It doesn't happen every time, and it does not seem to be particularly connected to high rpm or low rpm shifts