I have my Speedo out of my '82 and found the little white gear
that is engaged by the worm gear had slipped off it's shaft.
Put it back on and it looks like it will work, but it also looks
like it will slip off again.  Are there any suggestions here.
What type lube should I use in the Speedo, if any?

The back case of the Speedo is disintegrating.  It looks like I
will have to tape it up.

Bill