Z4 E89 diff noise puzzle

[gnl]

I have a 30 sdrive auto, 45000 miles which I recently purchased. It has what I describe a a dry metalic shooshing sound coming from the rear of the cabin. It’s there from a low speed, doesn’t vary much, seems worse after the car has been running for a while, doesn’t vary with direction and is there whether is in drive, under load, coasting or in neutral. I was pretty sure it was a diff bearing.
I’ve had it to a gearbox specialist who agreed it was diff bearings. They’ve had the diff out, changed the bearings.... and the noise is still there just the same!
They’ve had it back on a rolling road and had a stethoscope on the diff and still think that is the source of the noise. On Monday they are going to strip the diff again and take a second look.
In the meantime anyone got any suggestions? If it’s is coming from the diff I can’t think what else it can be apart from the grears themselves which sounds unlikely? Or could it stil be wheel bearings somehow being transmitted to the diff nd sounding like that’s the source?
Any clues welcome!
Thanks

 

[GuidoK]

In the meantime anyone got any suggestions? If it’s is coming from the diff I can’t think what else it can be apart from the grears themselves which sounds unlikely?

Thats not unlikely.
If a competent mechanic has changed the bearings he also did a backlash investigation and investigated the gear meshing with an ink test.
Not reading any of this I presume this wasn't done?

And which bearings were changed exactly?

 

[gnl]

Must admit I don’t know the answers to all of these...

I certainly believe them to be competent, there a reasonable size gearbox specialist who tell me they have done a good number of Z4 diffs in the past although always the smaller ones in the smaller engined z4s I know they changed the pinion bearings and assumed they had changed the axle bearings too although I’ll need to confirm this on Monday. They certainly sounded perplexed that what they had done hadn’t sorted it. I guess I’ll learn a little more on Monday when they get the diff back out......
I was just interested if anyone else had experience with this. I had read that the pre tension shim could cause this if not adjusted properly but know no more than that.....

 

[gnl]

So an update of sorts. I’ve confrimed with the garage that they fitted a full set a new bearing to the diff which they did. Said they old ones showed little wear which explains why it’s made no difference to the whooshing noise....
They have taken the diff off again and are in the process of stripping it, and reassembling in the hope that they spot something else but a, not holding my breath.

If the noise remains I think they will give up, but not charge. Fair enough. Question is where do I do next with this. I could live with it as it’s not terrible but don’t really want to.

Wheel bearings? Doesn’t show the usual symptoms of changing tone at different speeds or changing with direction changes but maybe it’s an odd one. That said I don’t want to get into the trap of spending out changing one thing after another until I hit lucky, and bmw want £120 and hour to investigate......

Any one any suggestions....?

 

[TONYL]

What tyres have u fitted
Ive got the same model with what sounds the same issue
The tyres are uniroyle rain sport 2 and are known for being very noisy especially if worn down
Have u any mates with the same car to swop them to see if it makes a difference
Apart from the diff and wheel bearings theres not much else at the back
Tony

 

[JamiesZ4]

Virtually identical car to the OP including mileage. Mine has made a very subtle low level whispery/whirry noise from the rear since purchasing back in April this year, as the OP describes, it seems more pronounced after the car has warmed up but its not a loud noise more in the background.

However having done 2000 miles, both short trips and run outs from my home in Ken to client sites in Cirencester, Cheltenham, Oxford and Essex so far since purchase with no performance issues related to this whispery/whirry noise I've decided it must just be the noise it makes as normal and so until something goes ping (or bang) will live with it

 

[Davidcliff]

I have same car and at 36,000 miles I have had two diffs from BMW. Thank goodness for warranty .
It made the noise you have described . Have a look at my posts in here .
Car all good now and whisper quiet , a good diff does not make any noise at all .

 

[JamiesZ4]

Good to read your comments David, so it would then appear i do have a problem, rather than the whirry noise being the norm. I need to book my car in for the battery terminal cable recall and I also have a failed roof issue so will get main dealer to check the diff at the same time.

 

[Bez]

You describe similar noises on mine. Currently it's fairly quiet but imagine it's not going to improve.

 

[nickyboy2]

Hi Guys
Im new to this but I have a 2011 23sdrive, just bought it and I have the same noise.
its done 50000 miles, and i wondered if you had any update since this was posted last year?
i am a fully skilled technician but been out of the trade for a few years. it sounds like wheel bearing noise to me but doesn't really increase with speed.

 

[Ds233]

I have a similar noise. It's more of a metallic clank when moving off at low speeds in the z4.
Had it into BMW multiple times complaining about it, they tested mine alongside another and said the noise is completely normal for this car. Bit strange as another garage had said the difference had metal shards in.... insurance refused to replace the diff as they said BMW opinion over a smaller garage would be correct. It's been about a year and a half it hasn't become any louder but it's still there. Hopefully nothing ever comes from it.
Seems my BMW has had a few build problems!

 

[mcbutler]

Any noise caused by tyres, diff, gearbox will change with speed.
You may want to investigate the prop centre bearing, only around £45 and an easy(ish) job.

I had my 23i box stripped and inspected by the guys who rebuild BMW's 'exchange' unit gearboxes because it whined in second around 1700 rpm and also in third.
They told me that it is very common for the getrag box to whine. I was unhappy with that so went to my local indy who agreed with the gBox bods and then took me for a drive in a 23i and a 3.0i manual to prove the point, both did exactly the same thing!!

 

[Cees Klumper]

The first E89 I test drove back in May had a slight whine in the rear diff. I asked the seller and he said his mechanic checked and claimed 'it was nothing'. Test drove the one other E89 he had for sale and it did not have any whine. So I walked away from that seller, after some online research showed BMWs are prone to this problem. It sounds (pun intended) like something that is relatively costly to fix.

 

[flybobbie]

My 2009 23i with 82k miles has absolutely no strange noises from gear box or diff. So any noises from there would have me concerned.
The only noise i hear is the clunking of the rear floating drive shafts when i first reverse.
German engineering, mind you could be worse;
https://www.youtube.com/watch?v=ROnb5ouBjNc
2:30

 

[Spawny lad]

My e89 3.0 has a whine on diff when running with no power ie on over run .
Only had her 2 weeks the dealer sent it strate to garage to be rebuilt at a transmission place.
Its was re fitted yesterday but still a very slight whine.so they are using differant oil on monday.
Hope ok then.
Or its off again.thank god for my 3 month warranty this is not cheep.
Love car appart from this.52k full bmw service history appart from last one.

 

[iks]

Did you manage to solve the problem?

I have exactly the same issue on my car[2011 3.5IS] and its got worse over the past 4 years. No garage so far has been able to give me a solution and I now avoid BMW because they simply cost too much. Paid over £2500 on my last visit for a roof issue. The car passes MOT with no advisories but the shooshing noise has just got worse over the years. Especially loud when its been stood for a while.

 

[gnl]

Pretty sure it will be the diff....

 

[alanarg]

Hey, how's it going?

Sorry to revive this post, I just got a BMW Z4 E89 '09 sDrive 30i with 100k miles and it has the exact same noise you mentioned. Took it to a fine mechanic and he's quite sure it's the diff.

Could you solve your issue? Thanks for any update

 

[gnl]

It was the diff! Still sounded a bit noisy when testing but seemed to settle quickly and. been fine since. Fingers crossed!

 

[jamesgarbett]

Hi folks was this whooshing noise you describe there all the time or intermittent?

I get a very similar noise combined with a metal on metal "ting" but it happens every few seconds when I'm on the move

It doesn't seem to be linked to the auto box changing gear but I can't be certain