You might take a look at this:

http://www.vanagonauts.com/index.phtml?catid=229

that I wrote up many years ago for the Vanagon mailing list (don't know how
it ended up on the BTDT site) as it sounds like you're experiencing leaking
transmission seals.  This job certainly can be done with the transmission
and engine in place, though removing the axles is almost a must just to give
yourself some room to work.

I did this job in my driveway and on my back, so doing it standing up with
the vehicle on a lift should make for a pretty quick job.

Tom Young

----- Original Message -----
From: "Richard Koerner" <rjkinpb@SBCGLOBAL.NET>
To: <vanagon@GERRY.VANAGON.COM>
Sent: Wednesday, September 22, 2010 3:28 PM
Subject: Manual Transmission Leaking at CV Joint

Just got back from a 4,500 mile roadtrip without incident. However, when
parked in the garage, I noticed a leak on the concrete floor. Looked up
there....definitely leaking from the interface between inner CV Joint and 4
speed manual transmission. Wiped the floor clean, and next day a new spot
(about 4 inches in diameter) reappears WITHOUT having started engine or
moving vehicle. So not good news.....

I recently (about 6,000 miles ago) new Axles (Lobro CV Joints, rebuilt by
GoWesty) on both sides. I did add CV grease to the exterior of the new
joints; they were wiped clean for shipping and GoWesty concurred that they
needed additional CV grease. I used 1 tube for all 4 joints when I did the
installation. Did I overdo it and blow out a seal of some kind? Or just
coincidence?

I had previously (about 30,000 miles ago) replaced the original gear oil
with Redline MT-90 per List wisdom. Car and motor and transmission all have
now 186,000 of gentle freeway miles mostly. Everything shifts, runs, sounds
normal.

So, before I head to the mechanic, I wanted to get some advice....what is
the probable problem, and what is the probable fix? Can it be done with
transmission in place and still connected to engine? Any idea of what this
might cost?

Rich
San Diego