BMW X5 E70 noise
 

I faced a weird noise issue with my BMW X5 E70 40d from year 2011 which for I would really need your guidance. The car is driven 150 000km.



The issue is the whistling/howling noise while driving 40-110 km/h and while NOT applying gas. When the gas pedal is pressed even a slightly the noise disappears and vice versa.

The phenomena doesn't appear right away while you start your car from cold and proceed to motorway. Typically it requires >30km driving so the car would be warm. Some time to time the noise also disappears.



The noise seems to be coming to the cabin from the rear side of the car.

The front drive shaft from transfer box to front differentials has been checked in campaign and no issues were found.



What could be causing this issue in E70? Does the support bearing for the rear drive shaft cause this kind of issues?



Next step plan is to change the oil to rear differential and to transfer case.
Thanks!

Could be a bad rear differential.


Symptoms are classic- under load it disappears, under load (part throttle) it goes away.


When the fluid is cold, no noise- as it heats up and the viscosity lowers, noisy.


If you search here and on bimmerfest for 'bad rear differential', you should find others that had issues- you can try and match up your symptoms. A DEFINITIVE diagnostic test will be hard, but you should be able to narrow it down.

GL!

Thanks, I'll do the detailed searching again.

Actually I've been studying the rear differential oil change topic quite a heavily and my car is manufactured on 07/2011 so it's basicly the first manufacturing month where the BMW Hypoid G1 is required for the differential oil. It seems to be/ require 75W-85 GL4 version instead of earlier GL5 grade, more common type of 75W-85 differential oil. I cannot get a big picture why they have limited the oil so after 07/2011 but it must be some quality, etc. finding since the earlier differential gears. Or otherwise the mechanics has changed on that month from some reason.

I couldn't find the exact 1:1 aftermarket oil to replace the BMW Hypoid G1 oil from markets. Tips for this one would be useful.



What is your experience, does the oil change typically remove the noise issues or is only way to fix the issue to change the bearings, etc. inside the differential drive?

If the noise is coming from the diff, then a fluid change isnt a 'fix'. Might change it for a while.


I just buy OE fluids if there is no direct replacement.... just not that much additional cost.

Change the oils, no major change
 

Changed the rear differential oils to OEM (Hypoid G1) and the noise got lowered a bit. Still you can hear it between 50-65mph. It requires something like 30miles drive before you can really hear the whistling noise.



Is this a common issue with E70's? Are there some bearing sets on sold to fix the old rear differential? Any tips where to get them without paying a fortune?



The OEM number for the rear differential seems to be 33107590914.



The rear wheel bearing couldn't cause this kind of noise symptoms? At least on this point there's no difference to noise depending if you are turning the wheels to the one direction or another. Main thing is the foot release from the accelerator pedal.

I'm getting a driveline whine too, mainly off throttle coasting. I'm about to change my fluids in hopes to get rid of it. But, unfortunately, I'm under the impression that it will come back, and eventually the rear diff will grenade. I'll replace it with a used unit.

Has someone been changing the rear differential bearings by himself for this newer version? Where to get bearing set?

Hey everyone, any resolution to this matter, I'm a new victim. My mechanic said it's common BMW problem, I asked him if I should go buy replacement oil and he said I'm wasting time and money, the diff needs rebuilding or replacement. He didn't even bother inspecting it.

That would be my indication to get a new mechanic.

Just replace the oil - cheaper first step. I’d go for a heavier oil in my experience - 80W-140 if you’re in a warm climate, 75W-90 if it gets cold where you live. Once the noise is there, chances are you will need to replace something soon but you might get away with it for a while with new lubrication


2012 E70 N63 50i