Speedo drive is suddenly very stiff

[Spaceman7Spiff]

So I've got the front end apart and decided to clean up the speedo drive. I washed it all out with solvent and then noticed that it is very very stiff to turn by hand. As in, I have to put it in a vise and turn it with pliers to get it to move.  This is especially weird because it seemed to be operating normally on the bike.  Is it just supposed to be that stiff?  I took it all apart as far as I could but I can't get the worm gear out because it seems to be held in with a roll pin installed in a blind hole.  I even tried to drill out the roll pin but it must be made of something very hard because my bits don't seem to be biting into it very well. Anyone encounter this before?

[dgorms]

If it wasn't broke, I wouldn't try to fix it. It shouldn't turn without the wheel spinning.