020 Transmission Codes and Specs

Transmission codes are listed by model and manufacture date on the right.

Before talking about acceleration, fuel economy or driveability, it's necessary to know ONE thing about that tranny you're thinking of buying ... will it fit?

First off, 8V trannies will fit in 16V cars by changing the clutch disc from a 16V disc to an 8V disc .. they're both 210mm and will work. 16V trannies will bolt up to 8V motors as long as a 16V 210mm clutch disc is used. Some early models had 190mm or other clutch and pressure plate setups that are not able to fit the 16V disc. This is fixable by swapping in a 210mm flywheel.

As to clutch release systems, they are cable operated and all the same.

As for electrical connectors? Two different types of backup lite switches. One is huge and fails often. It incorporates the "upshift indicator". The other types have a simple 2 pole switch. The big switch can be jumped on its two terminals that close to operate the backup lites. As a matter of fact, several model VWs have an adapter harness that does this. If you put a tranny in with 2 pole switch in a car with an upshift indicator, you'll have to do without it, but not the backup lites.

As for the flanges that accept the left and right drive axles? 2 sizes (90 & 100 mm) are available. It is sometimes possible to change these, but not always. If your new tranny has 90 mm flanges and isn't clearanced to accept 100mm flanges, you can often get around this by changing the joint size on the inner CV joints. If your new tranny has 100mm flanges, and the axles have 90mm CVs, you can often swap in axles with larger joints. If you don't clearance the spindles on some A1 and A2 cars, you'll have to install hybrid axles with 100mm inners and 90mm outer CVs. Otherwise, your axles might lock up when you tighten the axle nut.

All of this aside, there's one thing you can't change. Mounting possibilities. A1s use 4 mounts and A2s use three. The shifting linkage on both is different and can cause problems if the wrong transmission is chosen. Some 020 trannies have "holes" in the differential to accept A2 linkage. Some trannies have "studs" on the differential to accept the A1s 4th motor mount. Some trannies have BOTH. Know what you need and what you've got.

If you've purchased a transmission with a different sized ring and pinion than was originally in your car, you will need to replace the speedometer drive to the one that corresponds to your current final drive size. These are available at your local Volkswagen dealer.

Part Numbers:

020 3.6= 171 957 821 B (RED)
020 3.9= 171 957 821 A (WHITE)
020 4.25= 171 957 821 C (GREEN)

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