luckily I somehow still managed to keep track of the O-Ring. I took it out to clean out the channel and give it a little grease love so it's in a dish. I might replace with one from work though.You'll need the o-ring, too. I think it's a separate number.
Just a heads up..DONT be tempted to "teardown" the final drive if you have leaks....I’m hoping they did this for seals too. I’m about to tear engine down, but I need to find a good gasket and seal kit first