I have a Trans Specialties t-400 that has leaked since I got it. I finally found the port on the passenger side is the cause of the leak. The question is though, this one looks like it has a pressed in plug about half way back on the case, with the vertical rib in line with the dipstick. What do I do to stop the leak without having to take it out of the car? I think it is sealed and driven in. Can I seal it externally?

I believe that it is the band anchor lug for your front band. I've never seen them leak before. They are pressed into the case. I would think that if it is leaking, then the lug is loose in the case, it should be flush with the casting, if it is out some, then it has walked out of the case . I know the 4L80E's are bad about the rear band lugs working out of the case, when I run into this, I remove them completely, and drive them back in with some bearing retainer Loctite, then use a center punch around the lug to help retain it. But the ones that I have worked on for this were getting rebuilt. If yours is out, then you need to drive it in flush, clean it real good, and maybe try some rtv. I'm affraid you might have bigger problems though.

It's leaked from day one, and it seems to only happen after a run. The trans is coming out anyway and going back to be looked at. So they can reseal it or repair it then.