Gearbox leaking

Hello everyone.
Apologies in advance, I'm working on motorcycles but decided it was time for something else, so some things need a bit of asking before it makes sense, this being one of those things

I hope someone can help me with an issue with my MK1. As the title says it's dripping from the gearbox, from a specific location, so I have a few questions.

It's a 1983 1.5 with a 3-speed automatic gearbox. When being parked for e few days, there will be a small puddle on the floor, nothing that's really concerning when it comes to the amount, but something I want to get fixed before I stain a driveway or something like that.

The drip comes from the axel here (gearbox on the image isn't mine): Dropbox - File Deleted - Simplify your life
1: What's the name for this assembly with gas cable and everything?
2: What does this whole pivot arrangement that's throttle-activated do? Something with the kick-down or am I completely wrong?
3: Does anyone have a parts overview diagram, so I can get an idea of the parts, how they are put together, and what to order.
4: Does my gearbox have a specific number code?
5: What oil should I use for refilling?

Fingers crossed the gearbox doesn't need a complete rebuild. Hoping it's just a bushing of some sorts, that's gone bad over time…

The ATSG for the 010 Auto is here:
https://www.reflectionsandshadows.com/a1-tech/BIGATSG.pdf

VW trouble shooting guide:
http://www.cabby-info.com/Files/010TroubleshootingManual.

Lost knowledge thread:
https://www.vwvortex.com/threads/the-010-lost-knowledge-thread.4516976/?id=4516976

The accelerator cable runs over to the pull down arm, and the bowdon cable runs from the pull down arm to the throttle body.

The shifter cable attached to the shifter arm via a barrel bolt lock through the bolt.

The 010 has been know to go over 400Kmiles before needing repair.

So the question is is it leaking 90wt oil, out of the Diff, or ATF as there is a few things over the years that I have found to be the issue as when my pump by-pass froze up and shot ATF out of the Torque convertor seal, then there was the dredded seal leak that filled the Differential with ATF intermix.  

And well the last one that I had to replace was because the differential was destroyed by a Pea-Poor Rebuilt CV Joint.