You could be looking at Toast all right.
First thing - how many miles on it ???

Second thing you MUST check.....where the throttle cable connects to the
lever on the transmission, at the aft end of the throttle cable there's a
ball pivot.  It never gets lubed, It's even hard to see.  Not talking about
the throttle body either on the engine - talking about on the lever on the
trans.
If you can't jack up your van to really get under there, you won't be able
to check it.

On one trans that was fine in every way, except it didn't shift up into
3rd....
.............as I was pulling the trans I found this pivot point completely
rusted solid. 
( at the time  I had a known-near-new rebuilt trans, and put that one in,
and never got to try the 'old' one yet, but you gotta check that pivot. ) 

the jerking you describe - and fluid is full - sounds like a shot tranny. 
Scott
www.turbovans.com 

-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of
Dustin Jones
Sent: Monday, September 24, 2007 11:33 AM
To: vanagon@GERRY.VANAGON.COM
Subject: Need Help Diagnosing Auto Tran problem

While driving Saturday my 91 Carat  (192,000 miles) began acting weired when
accelerating after coming to a complete stop and seemed sluggish when
shifting. Every time I came to a complete stop and then hit the gas to
accelerate the van didn't go right away, there was hesitation before the
transmission went into gear, causing some weird noises and tire burnouts.
Went home and checked the AT fluid level, was fine, didn't smell burnt.
Sunday morning I pull out of the drive way and the van won't shift out of
first gear. Other symptoms: the van does not engage in the gear right away
when shifted. For example the van use to make a noticeable shift from Park
to Drive when engaging in gear, does not do that anymore. Also when on a
hill and in Drive, the tran makes weird noises and will slowly drift
backward. So I'm wondering is this a linkage problem or something along
those lines or is my transmission toast? Any ideas?