I have a 2008 A4 with the 7 speed CVT box and it has developed a noise that I can only describe as though it is dragging a large plastic item underneath (which of course it isn't). We thought it might be a wheel bearing as it sounds similar and appears to be coming more from the near side front so we changed that but made no difference. The drive shaft was on its way out so we did that as a matter of course but again no change. My fitter has had it on the ramp and there is nothing obvious at all so he is certain it is internal, maybe a gearbox issue.

The noise only occurred when moving but only when you come off the accelerator - as soon as you went back on the throttle it disappeared only to come back when coming off the throttle - the higher the revs when you come off the accelerator, the louder the noise. I have had to change the fly wheel recently as it was makings hell of a rattle when turning over the engine which meant dropping the gearbox out - it could simply be a coincidence but the new noise only occurred about a week after. My fitter doesn't believe the two are related as, although it was quite a labour intensive job, it wasn't especially complicated. We gave the symptoms to the local auto gearbox specialist and he was stumped so we are not sure which way to go - we could drop the gearbox back out and send it off but if it's not that then I am going to waste an awful lot of money.

If any one can point us in the right direction then is be grateful