I find that worriesome. By having the fill and vent at the top of the gear case leaves oil as the only alturnative. Grease could possible have voids around the gears. (Cornhead grease is best in this regard.) Since oil floats on top of water, it gives you no way to drain the gearcase or check for water except to remove the skeg. That would possibly damage the gasket and you might have to make one , if a new one is unavailable. . . 🙄
