In mid 84, VW change the 020’s transmission from 90mm output flanges to 100mm output flanges. Mainly writing all of this down with what I found out about my 100mm flanges today. I will expand this as I find more information about the earlier transmissions. There was a weird transition period from 83 to 84 where there were two case styles.

Bolts for axles to flanges: M8x1.25 (48mm long)
Torque Spec: 45 Nm (33 ft. lbs.)
Part Number for 6mm Allen head type: 113 501 229 D
Part Numbers for 8mm XZN Triple Square head type: 893 407 237
N91108201
W01331834815
ATM 893407237

Axle Nut Size: M20x1.5 (30mm socket required)
This is a self-locking nut (lock nut), and should be replaced every time.
Torque Spec: 240 Nm (173 ft. lbs.)

Circlip (Lock Ring) for the differential pinion shaft that goes inside the output flange: VW Part Number 113 311 287
Tool for removing: Lisle 44900 Lock Ring Pliers

Kit for output shaft seal, including circlip, cap, and seal: 020 498 085G or 020 301 189H

Output Shaft Seal for 100mm flanges (around the outside of the flange): 50mm x 65.2mm x 10mm (ID x OD x Thickness)
1.969″ x 2.565″ x 0.394″
Part Numbers:
National / Timken 710651
Febi 01519
Kaco 216415
88996656
020301189E
020301189G
020301189H
020301189M
020301189N
020301189R
020301189S
020301189T
020498189E
020498189G
02M409189
02M409189B

Output Seal for 90mm Flanges (Coming Soon)
Older pre-83 cars used a “Fat” seal 36x58x15

Flange Seal – this is a cap that goes inside the flange to cover the pinion shaft with circlip, it separates the viscous CV joint grease from mixing with the gear oil inside the differential: 020 409 289 B

Tool for pushing in axle flange: VW 201
Basically is a M10x1.5 at least 130mm threaded rod with a bent U shape to push down on flange. You will need enough clearance to get the lock ring pliers in.

Broke VW Reference DIY page:
http://www.brokevw.com/020flange.html