Whistling noise at speed when off throttle

[thecremeegg]

So if Im going at 70 odd and lift off and the car slows, there's like a whistle noise coming from what sounds likes the rear? I can hear it all the way down to around 40mph.

Could it be the diff or perhaps some sort of air leak? My diff does make noises when manouvering when cold but it has had a fluid change a few months back.

Thanks!

 

[RedUn]

Whistle or whine?

 

[Zed-X]

I had a similar sort of thing except that my noise was more "whirring" than whistling and it would only occur once up it temperature and on-throttle not off.

I've put it down to the diff oil level being too low and possibly not of the correct grade/viscosity, as when I took it into RBM and they drained & refilled the diff (and gearbox) with OEM BMW oils, the noise went away.

 

[thecremeegg]

Whistle or whine?

I'll be honest it's hard to describe but it could be a whine I suppose. Only hear it with the roof up interestingly

 

[j3nks79]

Could be diff or lathe shaft bearing in the gearbox of its whine when off power