The following article answers three very good questions customers often ask regarding Eurovan transaxles.
What is the life expectancy of any Eurovan automatic transaxle? Simple question, not a simple answer. All years of the Eurovan automatic transmission have proven to be potentially problematic. Almost all automatic transmissions, foreign and domestic, became electronically controlled after about 1990, and the Eurovan is no exception. The term “electronically controlled” means there is a computer (aka "controller," "control module," "electronic control unit (ECU)", or "transmission control unit (TCU)"), wiring, and electric solenoids involved telling the transmission when to shift, and into which gear. Because of their complicated design, quality control is extremely critical. Back in the day, it was pitifully common to have the AT on a brand new Eurovan completely fail in the first 50k miles. The lowest mileage failure know of occurred at only 16,341 miles! These early failures were typically quality control and/or computer related. A bad connection, a loose roll pin, or something seemingly inconsequential "brings the whole house down."
The design of the Eurovan AT is basically very solid. We know of Eurovan automatic transmissions taken apart with over 100k miles that were working fine as a preemptive measure, only to find they were less than 50% worn! A complete transmission failure (no forward motion at all) is almost always preceded by it going into "limp mode," a mode into which the computer tells the transaxle to go to avoid any further damage and get you home safely. When this happens, the check engine light (CEL) comes on, and the transaxle shifts into 3rd gear—and stays in 3rd. If this happens, it is important to get the vehicle to a shop ASAP. Even a transaxle that has not gone into limp mode can be on its way out. Checking for debris in the oil pan is a good idea, which is clearly evident during an oil change. VW does not recommend that the transaxle be serviced ever. GoWesty disagrees, and we recommend a transmission oil change every 15K miles, and a GoWesty External Cooler Kit.
So, if my transaxle starts acting up, how can I tell if it is an internal problem or just a computer issue? Good question. The automatic transaxle in your Eurovan is controlled by a separate computer. We know from experience that it is impossible to tell if a transaxle shifting problem or failure is due to a problem in and of itself (the transaxle), or rather due to a faulty control unit. We have experienced situations where a fresh transaxle either does not work properly upon install, or is ruined in short order by a faulty control unit. Indeed, we have seen people go through three transaxles in 100k miles when all that may have been needed in the first place was a new computer. You might say, “Why not just down load the fault code from the on-board diagnostic system, and let it tell you what is wrong”. That would be nice, but the reality is that if the control unit is at fault, it may not be able to tell you it is bad. It is like a schizophrenic person saying he (and his friend) is feeling OK that day. Back in the day, what most VW dealers do to cover their ass was sell a rebuilt transaxle first. After all, it is not shifting correctly so it was an easy sell. Then when you are all done, you get hit with the need for a control unit after the fact. Psychologically it is an easier sell since you are already in for a $6000 repair, so “What’s another grand?” That horribleness was actually “the good old days.” Nowadays, VW does not offer transaxles or control units for the Eurovan, at all. So, where do you go for a rebuilt Eurovan transaxle and/or control unit? Your guess is as good as ours, quite frankly. You just have to find a shop that has the expertise, or does business with a shop that has the expertise to go through one of these transaxles thoroughly and properly—first and foremost. If it does not work correctly, that same shop will hopefully have access to good working Eurovans of the same vintage to swap computers with. That is the state of affairs, sad but true.
What else can I do to keep my Eurovan transaxle alive and well? The main reason manufacturers went to computer-controlled transaxles was to help them meet the ever-increasing fuel economy standards. The programming in the TCU is designed specifically with that purpose in mind. The TCU software is programmed such that the transaxle is always in the highest possible gear for the present driving conditions. However, the TCU does not have eyes and ears like the driver. The driver can see what is ahead, and is therefore in a pretty good position to intervene when appropriate.
When driving along on a flat road at a constant speed, there is no need to intervene. It is best to simply let the TCU decide for you. But when driving in situations where speed and/or throttle demand varies constantly, you will find that your transaxle is constantly shifting to the highest gear possible in an effort to save fuel. Situations like stop and go traffic, changing terrain, and/or towing passes are good examples of when it might be a good idea to intervene.
For example, when driving along a highway and coming up on a heavy grade where you begin to climb and apply more throttle, the transaxle may down-shift from 4th to 3rd. As traffic and terrain changes, you may find the transaxle shifting back to 4th, back to 3rd, back to 4th, over and over. If the driver can plainly see that conditions are not going to change soon, it is best to shift into 3rd manually and keep it there until holding 3rd is no longer necessary. On steeper, slower mountain driving and/or when towing a trailer, you may want to manually select 2nd gear. By selecting a given gear manually, the transaxle will not shift higher than the gear you have selected. The result will be the engine speed remains elevated and, as long as you remain in the safe zone according to the tachometer, every is fine. Doing this will cost you pennies in fuel, but could save you thousands in transaxle repair bills.
• In order to shift from any gear other than P, N, or D, the button on the gear shift lever has to be depressed half way. Pressing the button all the way will not allow you to move the lever past D. This is by design to avoid inadvertent down-shifting at high speeds.
• Be very, very careful NOT to inadvertently down-shift to a gear that is too low! If you doubt your ability to do this safely, simply bring the vehicle to a complete stop, select the highest gear you think you will need, and start driving again. The TCU will control the transaxle up to the gear you have selected and not shift beyond that gear.
• Operating your vehicle is "manual mode" takes concentration and effort! Do not get distracted and forget that you are in a lower gear, or severe engine damage can occur!