sounds like it might be the intermediate seal between the bellhousing and the tranny, this would explain why it would be leaking between the sumps. there's a TIS bulletin for this, unfortunately, it involves taking the tranny out and doing some light or moderate disassembly. i have it posted in my webspace, at the request of sbcncsu (scott council). it is available here

http://plaza.ufl.edu/rroopnar/SI%20%...pter%20Cas.PDF

if you want to look at it and see if your leaks match its symptoms.