Auto Transmission Theory

[Chuck Hill <hilltech@netins.net>]

I've had a problem with my '86 5000 (85K miles) recently.  It operates
normally, until suddenly, you can't move any more, either forward or
reverse.  If the car sits for 20 minutes, it will work normally for
perhaps another 3-4 miles, and then again lose forward motion.  The
fluid has been changed once, the transaxle is OK, no noises, the
strainer had only the normal amount of fine stuff on it, no chunks, or
metal pieces.   Has anyone had this kind of symptoms/problem, and what
do you think the fix is?

Also, is there anywhere on the net that I can find a step by step
explanation of how the VW/Audi three speed transmission operates.  I
have the Bently manuals, but they don't go into an explanation.
Perhaps, some one of our list members who knows how this transmission
works could write up an explanation, and reference the pages and parts
to the Bently manual.

My first thought was to just swap out the valve body and accumulator
piston, but I would really like the satisfaction of knowing exactly what
happens in there to make it do this.

TIA

Chuck Hill