Another issue was that my driver's side inner driveshaft boot was rubbing the transmission housing. After a few hundred miles, the boot actually cut and threw grease everywhere. I am using heavy shafts, from "The Driveshaft Shop". They warrantied the boot, but the new one also rubbed the tranny, so I decided to grind away the housing.
I've put 100 miles on it, and there's no sign of wear, so I think it won't be an issue.
When I added a drain hole, to the tranny, I used an internal type plug, which had straight threads. Because the port was tapped using a 3/8"NPT thread, I would get an occasional drip. I swapped it to an external plug, which has the NPT thread. Now, the leak is gone.