Sounds as though you might have a sticky shuttle valve in the shift body. It is amazing how small a piece of crud it is that can mess up that part of the trans. If you are brave, or at all mechanically inclined, the valve body can be easily removed, and cleaned out. I did it to mine just after I got it, nine years and 110 K miles ago. Dirt in an auto trans is a big problem, especially for us Vanagon mechanic/owners, because there is no filter for the transmission fluid in a Vanagon automatic trans. Before disassembly, though, you can try any of the available "Miracle in a can" trans cleaners. Some even work as advertised.

Mark Erb <kasdtech@MAC.COM> wrote:  1988 Westfalia with 95,000 miles, AT fluid changed 25,000 miles ago.
AT fluid is at the proper level. No AT fluid in the coolant. The
problem that has cropped up is the transmission sometimes does not
want to shift into 3rd gear and will wind out until I let off the gas
for a bit then it will slip into 3rd. The reverse gear will sometimes
not engage right away then will go into reverse with a big clunk.
These problems don't always occur but will happen even with a hot and
cold engine. Anyone else have this problem? Thoughts? A solution
perhaps? I have easy access to transmission shops (AAMCO, Cottman,
even a shop that does german transaxles) but I wanted to at least
have some ideas before I discuss options with a shop or try to tackle
it myself. Thanks for any feedback. Mark

Evan Mac Donald

1984 Wolfburg
1985 GL 7 Pass.
1991 Carat Weekender
1972 Chevy P/U
1993 Bonneville