I have a 60Hp Johnson and just below the plastic water intake screen is a small drain hole where the water runs out. Unfortunately gear oil is also running out of this hole. When I look at the exploded view in my manual it seems to be in the outside chamber. What I mean is it appears to be on the other side of the wall where the water pump is located. I thought it would be water pump seal or O-ring, but it's not even on that side. Maybe a small crack? A friend told me to fill the lower unit up with grease and that he has done that often with old motors that leaked gear oil. Is that OK? 