VW 02J Gearbox Design Flaw – Killed Car!
The Octavia RS project car uses a VW 02J gearbox. It’s a 5 speed and was used on Audi A3 MK1, Seat Leon MK1, , Toledo, VW Golf MK4 and the Octavia MK1. In short, it’s used in a ton of cars.
Project Octavia
So what happened with the Project Octavia?
I haven’t opened the gearbox but 95% chance the retaining pin in the gearbox has sheared letting in the differential internals hit the gearbox casing. It’s major problem and it made the car completely undriveable.
For a full explanation on the issue, you can see this video. Super in-depth and it demonstrates exactly what can happen with these gearboxes.
What’s Next?
I could fit another VW 02J gearbox. But if I’m going to do that we need to open up the gearbox and disassemble it to fix the flaw with the differential on the new ‘box. Not a cheap job.
The alternative, also detailed by Diesel Dork is to fit an 02S 6 speed gearbox. He says this is a direct bolt in solution with a few mods.
The mods being the gear linkage. A custom mount needs to be made to support the bracket from the 02J gearbox.
And the other issue is the speedo signal.
The 02J has a VSS (vehicle speed sensor) mounted in the gearbox to read the rotation of the differential. The VW 02S does not use this and so does not have the required hole in the gearbox case. Fortunately, I hope, it’s possible to reprogram the ECU to take the speed from the ABS module. I haven’t done it myself, but I hope it’s as easy as described in this video.
Waiting
I’ve taken the plunge/gamble/dive and ordered an 02S gearbox. But it will be a month getting to me. I’ll be documenting this 6 speed conversion so if you want to see what happens, subscribe to the newsletter.
Video
This video is me crying about what happened and what’s next with the project.
