Project makes it home.
After getting the buggy home, I did a quick safety check of the typical things; brakes, steering components, lug nuts, fluid checks, voltage checks (static and charging output), and lighting. After making note of the things needing replaced (which in my mind was all of it, as that is pretty typical of me, wanting to go through each system and component so that I can verify, to my standards, that each component and system will function as designed and won’t fail on me while in use), I encouraged my wife to jump in with me and attempt a quick spin around the block, because why not, it’s supposed to be an adventure right?
After a few minutes of playing with the battery and starter, the 1600cc dual port VW engine roared to life, or more truthfully, coughed to life. Once running, I let it warm up for a few minutes while I got my license and cell phone, necessities for something like this. Finally, we jumped into the buggy, strapped in via the 4-point harnesses, and I threw the thing into reverse. Slowly I let out the clutch, as I am not familiar with how much power these 1600cc dual ports put out and what kind of throttle response I’ve got since this machine is new to me. And I kept letting the clutch out, and some more, and…then the terrible grinding could be heard.
So, it is a common thing among these Type 1 VW transaxles (swing and IRS) to have the reverse gear fail after lots of use, abused or not. The design of the reverse gear is such that the gear itself rides on its own shift rail and the reverse gear essentially floats between the main shaft of the transmission and the pinion shaft of the transmission.
As the transaxle wears, the travel of the reverse gear (inside the transmission) decreases and thus the reverse gear does not make full engagement with the 1-2 shift slider. Consider the 1-2 shift slider – its job is to be moved by the shift rail when you move the shift lever inside the cabin of the car. When you shift into 1st gear, the shift moves the 1-2 shift rail forward, which correspondingly moved the 1-2 shift slider forward and causes it to engage with 1st gear. When 1st gear is engaged it transmits engine power from the crankshaft, to the input shaft of the transmission, which is the main shaft of the transmission, which engages with the pinion shaft of the transmission, which is locked into 1st gear because of the 1-2 shift slider. The pinion shaft then engages with the pinion ring gear and differential gear which causes the wheels to turn. The reverse gear wears over time since the material is softer and it does not make full engagement with the 1-2 shift slider (due to poor shifting techniques by the driver).
The result of this is that the reverse gear tends to pop out of its engagement or causes a loud grinding noise and ultimately you don’t move. As this wear increases you eventually reach the point of no-return in that you effectively no longer have a reverse gear as the teeth on the gear become so rounded over that its only remaining feature is that of a paper weight. A similar thing happens when your other forward gears grind when shifting but it typically takes much more abuse to reach their point of failure.
More to come…stay tuned!