Final Drive and Transmission in a 1990 IDI? GM Synchromesh?

[Matteo]

Volks,
I read here that GM Syncromesh is popular for use in Jetta transmissions.
Does this also apply to the 1990 Jetta IDI? Someone asked me if the transmission is a syncromesh tranny. Not sure as I am a new owner and my other cars are all aircooled.
Further, when you fill the tranny, does it also fill the final drive, or are they separately enclosed and independent of one another?
I want to change my tranny oil, but am unsure whether to use 80 weight hypoid or the GM/Penzoil syncromesh.
Obviously confused. TIA for your help!

Matt

[Vincent Waldon]

Hi there... congrats on your new beast.... if nothing else you are going to find it warmer in the winter than your previous VWs !!

Like the air-cooled line VW worked hard to reuse parts, standards, etc during their various water-cooled lines.

As such, from the early Rabbits all the way to the late 1990s most of the A-platform (Rabbits/Golfs/Jettas)  used what is generically known as an "020" tranny...  4 or 5 syncromesh speeds, cable-actuated clutch, and a lever-based shift linkage.  It's one big case that encloses the main drive and final drive.

www.brokevw.com is the standard site for info on this tranny... and he'll tell you to fill it with exactly 2.0l or 2.1 US quarts.  There's a 17mm drain plug on the bottom and a 17mm fill hole on the side... you can also fill from the speedo drive hole on top.  A 17mm bolt with a couple of nuts cross-treaded on it makes a fine tool... supposedly the OEM Beetle sparkplug wrench will work as well.

Internet wisdom on the fluid is GM Synchromesh or Redline MTL.