Droning Noise ?? Problem is evading the mechanics. Any suggestions please

[Turnbulltj]

Hi Guys, new to the forum. My X5 2004 4.4 Sport has developed an audible drone specifically under power load. Can be felt through the car/pedal and sometimes displays itself as a whoo whoo whoo especially at speed.

BMW specialists have it at the moment. They have road tested and pinpointed it more to centre front. However on the Ramps with the wheels dangling, they cannot duplicate the noise.

They have stethoscoped front and rear diff and transfer case. All displaying some noise, rear diff seems to be the noisiest, but they are not confident of a diagnosis yet. Keeping the car tomorrow to do further tests.

I had all the diff oils and transfer case oil changed about two months ago and none showed any telltale signs.

Anyone experienced the same or maybe throw some light on the issue?

Thankyou.

[kkx5]

What tyres you running?

[Turnbulltj]

They're Pirelli. But the noise is definitely mechanical. Not to say they're couldn't be a contributory factor in the tyre noise.

But the main audible noise is def mechanical. Also it displays itself under power load, pointing away from just tyre/road noise.

[Olliefrom83]

Hi

I recently had exact same problem and actually took the car in to the garage thinking it was gearbox/transfer case related or a wheel bearing, the noise would change under different loads and speed.

mine was resolved by changing to star rated tyres, bizarre but true and not a single noise since, apparently the rolling radius is different on non star rated tyres for staggered setup causing all sorts weird issues with transfer box etc

That being said I would have thought Pirelli tyres would be ok on the X5?

[Merida]

Did you get this sorted?

Mine started doing the drone / whooo whoo noise under power, changing tone when lifting off.

Turns out the Rear Diff is goosed, now at the garage being rebuilt.  Was hard to tell if it was front or rear end noise initially but dropping the seats and removing the boot floor etc helped pinpoint if it was front or rear.

[Merida]

and  again.

Diff is beyond help, new one going in as unable to find one with the same ratio on the used market

[X5Sport]

Diffs are very hard to find and many end up having to go OEM at excessive cost..

[Jamie_E53]

What's the price of a replacement diff if you don't mind me asking?

[Pete]

To both posters - Have you got the correct sized tyres and wheels on?

Also, I had a set of wheels that someone must have put the tyres on the wrong way, then realised after some time and switched them. They were really noisy and you could feel a vibration.  Hard to get to the bottom of but if you run your hand over the tyre (as if the wheel is going fwds) it will dig into your palm if this is an issue.

[Merida]

[quote="Jamie_E53"]
What's the price of a replacement diff if you don't mind me asking?
[/quote]

New diff retail was £1666 + vat, my installer was very kind and let me ring and pay their trade price so saved a little but it was still £1500 + vat 

[Merida]

Had my car back over a week now, I can honestly say that it has NEVER been this quiet since I've owned it (almost 18 months now).  Think the diff has been quietly on it's way for some time, just a shame it didn't decide to get really noisy during the warranty period  >:(