Yesterday this 2 month drama got its solution. For the third time I visited the Audi Workshop in Växjö for consulting them on this problem.
I asked them if they had checked the hydraulic oil level, and they said Yes.
When checking the container, there was just 10 mm oil heigth in it. I asked them to fill it up and they could fill in about 200 ml.
Then I said: I can go for a test ride during your lunch-time, and did so. For 40 km I couldn´t repeat the problem I have had instantly after some 2-3 km before. I believe the problem is solved.
The workshop answered after lunch-time when visiting them again: Excuse us, we are ashamed...
I am happy, although I have had several bad nights thinking over how much this will cost. Now it was solved for free!
Stefan