I have been having such a difficult time with the primary and figuring out which end was leaking. So I pulled the transmission and decided to see if there were any major or weird leaks. I put this together to leak check it. I tried to set the regulator as low as possible, about 6 to 10 psi. I then put the rubber tip to the vent screw hole on the transmission top. Then I start spraying it down with soapy water and looked for bubbles.
I found the bubbles at my drain plug even with my new proper seal. So I pulled the plug to take a look. Here's the problem, the last little bit of the threads and sealing surface aren't there.
Silicon to the rescue. I put the plug mostly in and just coated the last couple threads. The instructions on this copper silicon says go finger tight, wait an hour, torque, and wait 24 hours. That seemed to work. No more bubbles there. Don't use silicon on engine parts, but on a transmission, you should be fine since there aren't any oil passages to clog.
The next bubbles I found were clear up here. That's really odd, because it has to be a porosity issue and it should technically be "above the water line", but I might as well fix it.
Black silicon here so it doesn't scream like the orange stuff.
I filled the transmission with Bell Ray Big Twin oil, so if it leaks, I can find the red trail.
I did this work weeks ago and I haven't gotten around to blogging about it. The drain plug seems to be holding.