Automatic Transaxle Failures in Vanagons: Prevention
The Vanagon auto trans is a simple and strong unit with a long service life. However it does have several issues that will need attention to prevent premature failure. Read on!
The Vanagon automatic transaxle is comprised of an automatic transmission section and a differential section. The basic design of the transaxle has not changed since its inception in 1972. It is a three-speed design. The automatic section has the designation "010." The VW/Audi 010 automatic transmission is extremely simple, very robust, and very reliable. It was used in the Audi 4000, 5000, turbo and non-turbo versions, Passat, Rabbit, Jetta, Golf, and many more models up to about 1993. It was about that time that VW, along with every other manufacturer, switched to more efficient—but far more complicated—electronically controlled 4- and 5-speed designs.
The automatic transaxle in Vanagons has basically only two failure modes, besides just wearing out. A well maintained transaxle will last at least 250,000 miles. If it does break it is usually either the transmission oil cooler or the seals that separate the automatic transmission fluid (ATF) from the differential oil (gear oil).
Oil cooler: On all water-cooled Vanagons, VW fitted a heat exchanger on the front (commonly referred to as the transmission oil cooler). This heat exchanger allows the ATF (automatic transmission fluid) and the engine coolant to flow in very close proximity. Since the engine coolant warms up slightly faster than the ATF, the heat exchanger acts to warm the ATF. Then, as the ATF becomes hotter than the coolant, the heat exchanger works in reverse and actually helps to keep the ATF cool. This heat exchanger was made of aluminum, and GoWesty recommended that it be replaced every 10 years or so, regardless of its outward appearance (and even if it didn't appear to be leaking externally). These coolers were available for around $200... then they went to $300... and then to over $500. That sounds like a lot of money to spend to replace a part that would, by normal standards, appear perfectly functional.
The problem was that when the cooler did fail, it failed internally. When this happened, it allowed the two fluids (ATF and coolant) to mix. So, the transmission would be filled with coolant, and the cooling system got contaminated with ATF. The result is a ruined transmission ($2500) and a ruined cooling system ($3500). We have seen some really long faces in our shop caused by this little bugger. So, replacing the cooler just made good sense. At GoWesty, we would replace this cooler on every Vanagon we sold with an automatic transmission and on every rebuilt transmission we sold, period.
However... notice the use of the past tense in the above paragraph... The plot thickens! The bad news: This little prone-to-failure bugger is no longer available at any price. Not to worry. GoWesty's got your back.
Introducing the GoWesty Automatic Transmission Cooler Kit. This kit is all you need to get rid of the factory oil cooler once and for all. Our kit completely eliminates the coolant part of the system, and it comes complete with a thermostat so that it is not cooling the transaxle when it doesn't need cooling. As the thermostat warms up, it forces the oil to the cooler (which is purely an air/oil cooler). So, no more danger of ATF and coolant mixing. If you still have the factory oil cooler on your automatic transaxle Vanagon, change it now!
Differential seals: Between the differential and automatic transmission sections there are two rubber lip seals that are placed back-to-back. Their job is to keep the ATF out of the differential, and the differential gear oil (DGO) out of the ATF. Since the ATF is under more pressure and is thinner than the DGO, the ATF usually ends up flowing into the differential section. For a while you will keep adding ATF and you will wonder where the hell it's going, 'cause it just does not leak out. It is flowing into the differential section, and will continue to do so until it fills up and starts spilling out of the breather at the top, making a huge mess. So, you should not have to EVER add ATF to your transaxle between services. If it begins to slip and you find it is low, you have to find out where it is going. If there are no external leaks, your seals have failed. You're probably thinking, "What's the big deal? ATF, DGO, BFD." ATF does not have the lubricity and viscosity required to properly lubricate the differential. So this will RUIN the final drive ring and pinion, which is THE MOST expensive part of the transaxle assembly. The good news is that these seals can be replaced without removing the entire transaxle. It is possible to remove and install the automatic transmission section in the vehicle and replace the seals. It adds about 3 hours to a normal AT service. GoWesty recommends just replacing them every third service, or 90,000 miles.
The bottom line is that in order to get the full life out of one of these transaxles (which is quite long, indeed) it is imperative to KEEP GOOD RECORDS, and DO THE MAINTENANCE! Click here for the GoWesty Vanagon recommended maintenance schedule.
