I took my Audi into the dealership to have them look at the convertible top. Had NO problems with the vehicle otherwise. Had just had my car serviced five days before locally. The dealership told me my car had a differential oil leak. That I could not drive it home. I got a ride home (180 miles!) and then I started to think. I called the man who serviced the car and he said he saw no leaks. I looked in my driveway...NO LEAKS. The mechanic who services my car said that with the Audi computer system, the computer should have notified me if there was a problem. Called the dealership and told them I would pay the $120 diagnosic charge, but didn't want the repair done. They said they had already ordered the parts and I would have to pay for the parts. I didn't even ask them to diagnose anything except the problem with the convertible top. Now I have to pay them almost $1000 to get my car back and they haven't fixed it and I don't think anything was wrong with it in the first place. What is the deal with the differential????? Please can somebody help me. I have never had a problem with this car before and keep it serviced etc. Have owned the car for two years. Thanks for any help I can get