Question: Will a more powerful engine reduce the life of my Vanagon transaxle?
The short answer is "yes," but it's a bit more complicated than that... read on for the straight dope.
When driven normally (read: conservatively), a higher output engine will not necessarily reduce the life of the transaxle. A higher output engine is capable of putting higher stress on the transaxle—and everything else, for that matter—but you have to think about it in terms of duty cycle. The fact is that 90% of driving does not require any more power than what a stock engine provides. About 10% of the time—when you want to climb a highway grade and keep up with traffic, for example—it sure is nice to have the extra power.
The extent to which a higher output engine will reduce the life of the transaxle is directly related not just to the output of the engine, but to whose foot is on the accelerator. I could put my 82-year-old father behind the wheel of a Vanagon with a Chevy V8 in it, and he'd probably get a longer life out of the transaxle than my 26-year-old son would get out of a Vanagon with a stock 1.9-liter engine. (My son, as I'm sure he will admit, has a pretty heavy foot!)
Generally speaking, we are not seeing a direct correlation between higher engine output and reduction in transaxle life. Part of the reason is that the Vanagon transaxle design is very robust and is, in fact, capable of handling much more power and torque than the original waterboxer generates. Another reason is that GoWesty rebuilt transaxles really are very high quality—we don't cut any corners, and we actually improve the design in several ways during the overhaul process. For example, we beef up the main shaft ball bearing bore, we always replace 4th gear and all of the engagement parts for 4th gear, and on many transaxles we add factory VW main shaft ball and pinion double-row tapered bearing oiling plates.
A high-quality rebuild, practical upgrades, and a gentle foot—that's the winning combination for transaxle longevity!
President, GoWesty Camper Products
Despite the information contained in this article, GoWesty will not warranty our rebuilt transaxles when used in conjunction with a non-Waterboxer engine conversion (like a Subaru engine, for example).