Re: impeller and hot motor
If it leaks out of there that is fine. It is just spent cooling water at that point.
The shift rod seal is a fat little o ring. It is serviced by driving out the bushing which holds it in place.
SO you resealed the gearcase except for the shift rod seal, the rest of the seals I mentioned are new?
If you put a new drive shaft seal on, and it is still leaking badly due to a worn shaft, I would personally get a good used shaft. Post a wanted ad at aomci.org in the webvertize. You could try a sleeve, but have never tried on myself.