Read a really good article form an American site, hence the "Eurovan" references.
All years of the Eurovan with an automatic transmission have proven to be potentially problematic. Almost all automatic transmissions, foreign and domestic, are electronically controlled after about 1990, and the Eurovan is no exception. The term “electronically controlled” means there is a computer, wiring, and electric solenoids involved in telling the transmission when to shift, and into which gear. Because of their complicated design, quality control is extremely critical. It is pitifully common to have the AT on a Eurovan completely fail at 70, 60, or even 50K miles!
The design of the Eurovan AT is basically very solid. Almost all of the failures that we have seen have been quality-control related. A bad connection, a loose roll pin or fastener, something seemingly inconsequential “brings the whole house down.” Failures often come without warning, leaving folks stranded. Some of our customers have opted to have their transmission completely gone through before it fails as an extra measure of insurance, and save money and potential inconvenience. We have taken Eurovan automatic transmissions apart with over 100k miles that were working fine as a preemptive measure, only to find they were less than 50% worn! The bottom line is this: If a Eurovan automatic makes it past the first 100k miles or so without a failure, the chances are good it will go the distance, which should be at least 200k miles between overhauls.
Most of the failures we have seen have taken place AFTER the end of the VW factory warranty (25k up to year model 2001, 50k for 2002 and 2003 models), but before 100k miles. Eurovans with between about 50 and 100k miles are in what we refer to as the “danger zone.” A transmission failure is almost always preceded by debris in the oil pan, which is clearly evident during an oil change. That is why we recommend transmission oil changes every 15k miles (every third engine oil change or so) until past the danger zone, and then every 30k miles thereafter (interestingly, VW does not recommend ANY service to the transaxle AT ALL). These oil changes may reveal a failure about to happen, or at the very least reduce wear by renewing the fluid.