Premature wear in various multi-link suspension components can cause noises that are difficult to diagnose. Worn suspension parts can also cause uneven tire wear and create steering alignment problems.Google+
Car Problem Reports
Audi A6 Quattro Premature Wear in Multi-Link Suspension Components May Cause Noise
Audi A6 Quattro Problem
Average Mileage: 58,551 mi (47,102 mi - 70,000 mi)
Bought a CERTIFIED pre-owned Audi A6 at a dealer in Southern California. After about a week I started hearing squeaking noise when I make a full turn. Does not happen very often but when you drive the whole day you hear the squeaking noise from time to time when you are parking and reverse out of a lot. Had brought my A6 to 4 different Audi dealerships for inspection but none of them had a clue where the noise is coming from. One dealership repacked and resealed my front calipers but was still making the noise. The other 3 dealers could not even diagnose the problem. Until now I still have the same issue and its embarassing when you hear the noise when you park and people are near the vehicle and look at my car.
Visitor, 2005 Audi A6 Quattro, 70,000 mi
The same problem