Originally Posted by swamp2
3. I expect there is nearly a zero chance that they mistakenly changed your DCT fluid but it did happen to quite a few cars and most got the wrong fluid and had serious tranny problems that resulting in them being replaced. Double check with your dealer on this.
As stupid as it would be for them to still be doing this, I would definitely get my hands on the actual service ticket from your visit. Preferably before starting this discussion.
You can search the forum for this topic, but as swamp pointed out it is terminal. Not eventually, but the moment the wrong fluid is put in and the car driven.
From what you described it sounds like the pitch and volume changes with speed, but cycles each gear. That doesn't sound like rearend to me and they shouldn't have been anywhere near anything else engine/trans related that should cause this. Could be coicidence and some other issue. We hope.
edit - just noticed you said also when revving in neutral. That's not likely to be the DCT either, is it?