You DO like adventure, don't you?

A couple of things:

a) Service Records - with specific reference to the transmission-
cooler if automatic.

b) Check the _entire_ Synchro system for leaks. Check, most
especially, the CV joints and axles, transmission & differential seals
and so forth.

Keep in mind that the Syncro system as used by VW is an adaptation
from Audi, and not really designed against a machine as  heavy,
awkward and underpowered as the Vanagon. And if it starts to fail
there are perhaps half-a-dozen mechanics worldwide who might be
comfortable servicing it - if you are lucky.

After which you are faced with the typical 22-year-old-vehicle-that-
also-happens-to-be-a-VW issues. Starting with rust and ending with
suspension and steering.

Peter Wieck
Melrose Park, PA