There are lemons in every bunch.  I have had two automatic Vanagons, both
with high miles on the trannies.  Both trannies worked excellent and have yet
to cause me any problems (I sold the one '84 GL and I still have the other at
166k miles, 91 Carat).  I had one 85 manual tranny Vanagon.  It shifted like
trash compared to my earlier experience with VW manual transmissions (Jettas,
Rabbits, and Golfs) and finally decided to stop going into 3rd and 4th gear
without double clutching (syncro hub syndrome, common to these vans).  The
van had 200k miles on it so I just parked it, sold the motor, and am
currently parting it out (body is just too rusty to justify spending money on
it).
So my two automatic tranny experiences have been great and my one manual
tranny experience has been poor.
I get around the same fuel mileage with my automatics (18 city, 20 highway)
and take off speed is about the same as well (can you accelerate faster with
a manual transmission Vanagon when your first gear is so low?  I don't think
so).
So my opinion is, automatics are generally more reliable, have less problems,
work great, and really have none of the draw backs that is normally
associated with an automatic versus a manual (poor fuel mileage or
acceleration).
Getting your automatic portion of the transmission rebuilt is around $700 so
rebuilds aren't that much more than manual transmissions either (unless you
trash out your differential section which is rare) and you have to have them
done less often (manual transmissions every 100-150k miles average,
automatics every 150k-200k miles) so your overall cost of ownership is less.

My two cents,
Ken Wilford
http://www.vanagain.com
John 3:16
Phone: (856)-765-1583
Shop:   (856)-327-0027
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