Gearcase oil leaking from lower unit - 1994 - Johnson 88spl

Just looked in the garage and there is a pool of gear oil below the outboard. Boat is used weekly and it just started leaking. Oil is coming from the hole near the screen on the lower unit (see pic). Is it hard to replace this seal? Do I need any special tools. I've pulled lower unit before with no problems so if it's not too major I'm sure I can do it. I'm supposed to take the boat on vacation to a lake house in a few days so I need to get this fixed fast.

Any advice and suggestions would be greatly appreciated!

Thanks,
Scott

Re: Gearcase oil leaking from lower unit - 1994 - Johnson 88spl

Hold on before you do anything! That little hole, that's an exhaust port. Unburned oil from your motor will run out that hole. Are you sure it's gear oil? Is it black or really dark in color? If so it's engine oil. It can happen from sitting without being run for a few days or weeks. When was the last time it was run?

Re: Gearcase oil leaking from lower unit - 1994 - Johnson 88spl

It was run 4 days ago. It is normally run every weekend. I've had it for about 4 years and run it most weekends and it has never done this before. The oil is not real dark but it has that gear oil smell to it. I just drained the gear oil and there was no water in it. The funny thing was the last bit of oil that drained wasn't black like all the rest, it looked like it was almost new. This makes me think maybe gearcase was overfilled and some clean oil stayed at the top in the driveshaft housing.

Tell me if this is possible - The lake water last weekend was 95 degrees so maybe gearcase got warmer than normal and burped some oil out the top driveshaft seal if it was overfilled.

Let me know what you you think of that theory, my imagination my be running overtime and I may bwe worrying about nothing.

I think for now I'll run it some more with new gear oil and see what happens and check the oil frequently.