Hi again,
we already found out about the problem some weeks ago, but since some were interested, here is the problem:
He aligned the teeth carefully, the "Tragbild" (no english word i know, sorry - meant is where the surface-point of the teeth touch the "worm drive") is so that performance will not suffer, and no additional wear will occur.
Anyway, the turning-around is now a smooth and even 30 nm, during several revolutions, measured with torque wrench.
I think the worst is not bringing the '66 300 kg Coventry grey cast block back to life, but this rear axle. God, what a construction.
Thanks and greetings,
Catfish