A4 3.0 TDI Auto - whine when coasting from rear

[GrantP]

Hi All,

As above I have a 56 plate 3.0 TDI auto on 70K miles, full SH, when coming off the throttle and coasting there is a distinct whine from the rear end.

Its most noticeable at about 30-50mph.

I guess the first thing to do is change the rear diff oil, has anyone had this symptoms and how did you solve it?

Any help/advice appreciated.

 

[Arnie013]

The fact you've said 30-50mph leads me to believe it could possibly be a wheel bearing. Can you not hear it at all if you're not coasting? Or is it just quieter? Also does it seemingly change pitch in relation to speed?

 

[GrantP]

No, only while coasting.

Not a wheel bearing, I know what that sounds like, rear diff seems the obvious choice.

 

[Arnie013]

Not insulting your intelligence in any way but could it be a tyre? I had the same problem on my old S3. Though it was the diff or haldex but the tyres were due changing, changed them and the noise went.

 

[GrantP]

No offence taken, however it does sound like a mechanical whine. I'd be surprised if it was tyres.

Could always try putting the fronts on the back to see if it make any difference

 

[jdp1962]

A4s do have a habit of generating more road noise when the tyres wear.

 

[Paul B7]

A4s do have a habit of generating more road noise when the tyres wear.

The B7 A4, the A6 and Passats from the same era AND the more modern A5 all can exhibit strange if not abnormal tyre wear on the rear causing noise and premature wear.
There are many stories on the net about how the VAG group is once again in denial about this problem but a real issue it is, guess how I know !