I have a 2004 A4 1.8T Auto. I heard a wierd sound today when I was driving, everything was going ok, then I needed to reverse, so I put car in R (auto trans) and then again in D and I heard a sound like a whirring as I hit the gas, coming from the back (I think, that's what it sounds like.) It almost sounds like what the turbo is supposed to do and at the same time, but louder, stronger and "bassier." Kind of like metal on meal without oil... any ideas? I also, in my old Acura, the oil hadn't been changed in forever and it made the same sound, so I changed the oil and all was ok, but I know that I don't need to change the oil.... THanks

 

sounds like a warranty issue car is only 2 years old (whats to say the tranny is leaking ATF and you didn't notice??)

 

Starter?

Audi's starter switches are notorious for going out and sticking in the start position. It will motor your starter in Park and Neutral. So when you transition from R to D, whirrrrr, the starter runs. If your car were older or had 70K miles I would totally say this, but for so new of a car, it would be odd to me. Have you had any odd power losses like headlights won't work but the blinkers do or only half of the car radio plays once in a while. Anyway, if it happens again, the starter is about where you sit so it could sound like it is behind you. But listen to it and see if it sounds like a starter turning. If the switch sticks, you can just twist it back ever so slightly and it will unstick. The real fix is to replace the starter switch. 30 dollar part, 1.5 hours labor.

Anyway, this is a reasonable guess so listen to all the guesses and or help us better understand the noise.

 

but I know that I don't need to change the oil how wrong you are, it also doesn't mean you don't have to check the level in the service (I think filled for life is the worst possible term used by any manufacturer because its little understood and leads to neglect)