[Mulv80]

Mike, When you drain the lower unit oil after a few trips it should come out looking the same as when it went in. If it comes out milky or a carmel color it means water is finding its way in there some how. If you find water in the lower unit the simplest thing to check first is that you have gaskets on the lower and upper oil screws. I usually replace these gaskets everytime I change the lower unit oil. If they are not the cause of the water intrusion the lower unit should be pressure tested for leaks and resealed.