Automatic transmission failure

["Dave C." <conner@cfm.ohio-state.edu>]

>On 4/08/97, Luis Pastor wrote the following re: his 1991 Audi 100 (European
spec)...
>From: "Luis I. Pastor Turullols" <70624.426@compuserve.com>
>Subject: A FAILURE IN THE DESIGN OF AUTOMATIC TRANSMISSION
>   I have found the problem with the AUDI 100 automatic transmission.  The
sleeve that moves >through the spindle is responsible for the break of the
oil retainer that separates the ATF from >the SAE-90 oil.  When these oils
are mixed, the timing gears are worn by unsuitable lubrication. > Because of
the number of problems, AUDI should have taken preventive measures,
replacing the >faulty gear boxes.   AUDI assembles two kinds of gear boxes:
AUDI and ZF.  This only happens to >AUDI boxes. Does AUDI deny they have a
faulty design?. It seems so.  I haven't received an >answer yet about my
letters sent to Germany on this topic.
>        Thank you,
>        Luis I. Pastor

Mr. Pastor is in Spain.  I wonder if what he says is true for cars sold in
the U.S.  I know there have been problems like this with the US Audi 5000's
and 100's.  There was a recall to replace the final drive gear oil with
synthetic.  But there is also the other problem with leaking between the
final drive and transmission.  
Bentley does not mention the two kinds of gear boxes...Audi and ZF.

Does anyone know if ZF gear boxes were installed in any US cars?

How can one tell the difference between Audi and ZF?

The sleeve described by Mr. PAstor appears to be illustrated by Bentley.

Does anyone know about preventive measures one could take to fix the problem
with the sleeve before it fails and destroys the gears?

I've got two cars with the auto trans and feel like I'm on borrowed time.
TIA for any comments.
DC