>The "slider" referred to earlier...is it unique to
>Syncros or is it a common manual tranny part, and if
>so, is it internal or external?

The "slider" is actually the outer part of the internal 3rd/4th shifting
mechanism that actually moves between the two gear positions. The hub it
rides on is actually the part that breaks on all Vanagons at some time.
The original design was the same as most all other slider hubs in all VW
trannys and seems to not be an issue in the earlier low powered engines
with less weight to push. The forces applied to our newer rigs appears to
make the marginal design fail regularly. (I am not an engineer mind
you...just a rebuilder)
 Most all rebuilders replace the hub with a newer design that MOSTLY
cures the problem. I use a custom built hub that is from a different
material and manufacturer and so far has been flawless. On disassembling
cores, I have seen some genuine VW factory replacement hubs that have
cracked. Although that is rare, it can happen.
Hope that helps and holler if any questions.

Daryl of AA Transaxle
Duvall, WA. (Seattle area)
(425) 788-4070
1-877-377-0773 (toll free)
aatransaxle.com (web site)