Hi Baldy,
Yes, the second gear detent seems to lock in fine whether connected or disconnected. So I don't think it has anything to do with the linkage being too short (if that's where you were going).
It's possible that the fine metal shavings were in part from a thrust washer (I was beginning to wonder about that washer and the role it plays in the gear shifting), however the old 2-3 gear shifter fork was ground down a good 16th of an inch which is why I assumed the residue was from that.
So tell me about this thrust washer. What exactly does it do?