Roscoe, you're right on...
Loctite makes a whole series of gasketing compound. The one I think is most popular is 515. It's anaerobic, which means you don't get hardened globs inside the trans like silicone will do.
You can probably pick some up at a local bearing supply house or online. You can also do some research at
www.loctite.com
The permatex should have sealed it though... you sure all bolts are tight and the faces were flat with no burrs, nicks, etc?