Right before our plane trip to the west coast, I noticed a gooey black blob under the driver side axle. Since the new engine insert a couple months ago, there had been no leaks but I had recently noticed a burnt oil smell after longer runs. The gooey blob was totally new. It was like jello pudding with a film on top and the color of tar.
After a quick search on the Samba, I felt pretty confident that it was a failed differential flange seal. The good folks at Van Cafe had the flange seal, washer and lock ring ready to go and shipped that day. I also ordered a replacement hose for my oil pressure gauge - ouch $30 -. As I get into this project, I'll keep posted - for one I am not sure whether I need to disconnect anything but the inner CV boot and axle. That would be nice if I could avoid disassembling everything from the wheel in. I also will re-grease all the CV's I get into.