I have a 12 tooth pinion gear (final drive) that was sold to me and advertised as an HG part. Probably a Oliver-Cletrac part, but won't work in an HG. Very good condition--- only blemish-- tiny striations running the long axis of the teeth. Reasonably priced.
Do you know if it will fit an OC-3. My farther has has told me that the bearing spun on the drivers left on his tractor. I have not opened it up yet to see the damage. I am going to gues that if it does not fit HG it wont fit OC-3 but worth checking out.
Let me know if you need any final drive parts for a late'40s (or similar) HG. I've got most of it.
Dick