I left my car at Steffen's place on the return trip from the Rømø Motor Festival.
Nothing wrong with the shift mechanism (note the high-quality forks).
Separating input shaft from main shaft reveals 4th and 3rd gears.
Dog-teeth on 3rd shifting sleeve worn round - that doesn't help.
But the real problem is this: all-crooked nut and synchro-band inside synchronizer!
Synchro-band has kinked and somehow jammed under the nut - locking everything up!
Here the kink is visible on the left band.
This is how the nut should sit - not allowing anything to go under it.
Steffen found some old original stock (OOS?) in the basement - yes please!
Compare the perfect teeth on the new dog-ring on the left with the worn on the right.
Nice and pointy dog-teeth on the shift-sleeve also - excellent.
The reassembly begins - additional new parts ordered from classicalfa in the UK.
BTW, this is from my 2nd gear - only synchro we changed when the gearbox was originally refurbished (only 5 years ago - bad quality?) You can watch my videos; I know how to change gear! I believe there has been a period recently when it was almost inevitable to get bad quality parts sourced from China. Last time we ordered all parts from Myalfa; wouldn't they have good quality?