3rd member gasket leak

Go to a motorcycle shop and get some sealant they use to seal engine cases with. Like Hondabond 4 or Yamabond. Use it with your gaskets, torque it down and don't worry about it.

I've split a few old Honda cases and resealed them with Hondabond and never had a leak. Crap, the stuff could probably stop a leak on a Harley.

Permatex Aviation Form-A-Gasket works pretty good to. It's fuel/oil resistant and doesn't harden. Just make sure you wear some rubber gloves and have some mineral spirits on hand when working with it because the crap has a way to get all over things if you're not careful and is messy.

I'd go with what they use on motorcycle cases for best results.