I discovered a major design flaw with the VW 02J gearbox design. How did I find it?
A MASSIVE bang and then broken sounds.
Driving along in 5th gear, bang and then broken noises from the gearbox area. Turns out there is a fundamental design flaw with the differential. A small pins secures a big pin which in turn supports the sun gears. The small pin breaks, the big pin can slide out and hit the gearbox case.
Which I think is what has happened to the Octavia RS project. Car seems like it would drive normally apart from the sound which I think is consistent with this broken pin.
Instead of getting another 02J gearbox I’m going to take a gamble and try an 02S. Stay tuned to see how it goes!