2005 D5 V70 AWD Whine from rear.
 

My 120k AWD has a noticeable whine from the rear. It can be heard between 50mph and 70mh as anything over this and it is masked by road noise so it is not a very loud whine.
It is only present when the drive is not under load from acceleration or the vehicle is slowing, so the speed is constant.
It drives me mad on dual carriageways as this is the speed it is most noticeable.

Accelerating or decelerating and the noise disappears.

I took it into my local Volvo independent who cant confirm if the noise is normal or not and suggest I leave it to develop as they can't identify the source.

Has anyone experienced a similar noise or have any idea if this is a trait of the rear diff and nothing to worry about.

I've never had any noise from the rear, so it's not "normal".
Have they checked that there's some oil in the diff and made sure it's not just wheel bearings?

Check the rear wheel bearings first,but the rear bearings in the diff become noisy. I have just fitted a used one to mine for £380

Hopefully it will be a wheel bearing. I have had to replace one on the back of our V70, I had to let it get quite bad, probably over 3-4 months before I could indentify which side it was.

Check rear brakes, they first whine, then beep, then the caliper seizes up, as happened on both my (previous) 1995 850 T-5 and (current) 2002 S60.

Definitely not associated with the rear brakes as calipers, discs, pads and handbrake cables have been replaced this year.

Rear Diff
 

I have found one on Ebay here

http://cgi.ebay.co.uk/ws/eBayISAPI.d...MakeTrack=true

Is this what you replaced?

Postage might be a few bob :)

(Check out where it is located)