Finally, I have found what causes the sound!!!
As soon as I started spraying lubrication on the steering dampener, there was a noticeable improvement. I continued lubricating and turning the wheel, until it no longer makes any noise. See attached photo
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Johannes
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Audi S8 -99, Pearlescent, Alcantara/silk napa leather, Burr walnut insert, Alcantara roof lining upper pack
A8 32V engine
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Jeep Grand Cherokee -98