WHINING ROTATIONAL NOISE FROM FRONT LEFT SIDE WHEN SLOWING BETWEEN 60 MPH - 40 MPH

[IAND]

over the past 2 yrs of owner ship of my 2010 e70 x5 I have noticed a rotational whine when slowing in over run from 60 mph to 40 mph. The noise is more prominent at 55 mph. My local BMW main agent investigated the issue and swapped the front wheels for the back which fixed the problem. The time came for me to fit 4 new run flat tyres so I opted for the pirelli scorpio as the previous were Michelin run flats and I thought the noise problem was the tyres. My first long run was 10 days after tyre fitting with a touring holiday round Europe. The whining noise was back and as we were in Germany I visited a BMW agent near Munich who after extensive testing which took all day, decided it was the front differential at fault which was then replaced. No it wasn`t !. So they then replaced the transfer box. I collected the car and drove about 50 miles to our accommodation to find the noise was still there. I gave up with any further investigations as this issue was ruining our holiday so decided to carry on and sort it when I returned to UK. I have been to an independent BMW service agent who have done extensive tests without any positive answer to the issue. What Now? Any ideas would be much appreciated as I am running out of ideas and Money.

[marti]

Wheel bearing..??

[IAND]

Thanks marti have also put that issue to the engineers and they have tested for same by steering left and right during whining noise without any change. It is also a question why noise disappeared when moving wheels from back to front with the Michelin tyres. Also wheel bearing would probably get worse in time, but this noise has done 12 k without any change.

[marti]

Is it actually coming from the wheels...maybe coming from the engine bay...possibly one of the belt tensioners / alternator?

[IAND]

thanks for your interest marti. It`s definitely wheels or transmission between output from gearbox and front left drive wheel. To prove it I have put drive into neutral while descending a long slope at the fore mentioned speed, engine at tick over revs. and the whining is still heard . The other option may be to remove the run flat tyres and try none run flats, or have the front wheel bearing left side replaced to prove a problem with it.