Micky, if you can not find a new one, you may be able to repair and dress the pitted one in the area where the seals ride.
Funny, mine has leaked a drop or two a week for years and today when I checked the boat there was at least an ounce all over everything. Was rebuilt about 15 years ago, so I will be right behind you on the tear down. I wonder if the cold has caused the seals to shrink up? Is your's also in the cold?
Good luck on the shaft.
Regards, Bob K