Since you stated that you took out the shift pivot pin, and seemed to successfully reinstalled it back and it is sealed again, does the shift rod move through the forward, neutral and reverse gears and work correctly now? Can you put it into forward gear and the prop spins forward? And neutral it spins either direction, and reverse only in reverse? Because if it doesn't NOW is the time to fix that issue. Not later when it is all reassembled again... And since you have it off, NOW is also the time to positively make sure the pivot pin IS properly sealed and not going to leak again. That could mean installing the proper new gasket or "O" ring.