Rear end (diff?) whining noise...anyone have the same?

[spenny_b]

Hey guys,

Got my M5 back on Saturday after it had spent a month with my BMW dealer having a few things addressed, but primarily what I perceived to be a differential whining noise.

**not a placebo effect from Darkshears thread....but of course, hope that Darkshear does come out of his situation better than before**

So, we noticed this noise in the summer, windows down whilst my daughter and I coasted through my town (which is an ancient town in the UK with double/triple overhang buildings and narrow streets - great for amplifying these sorts of noises).

Car was stone cold, gearshifts set to S3, and off-throttle from 15mph to a rolling stop we could hear a distinct whine from the rear. First thoughts were differential, not gear related, just speed.

Seeing this thread, specifically ChrisNich117's comments starting at Post#18, made me think I was hearing the same as Chris had.

The day before the car went to BMW, I mounted a GoPro to the rear bumper and managed to catch it, audible at approx 30secs:

BMW say they've tested repeatedly for a number of mornings, they could hear the sound, but were unable to track it down.

A month later, after communication between them and BMW UK (and quite possible BMW AG), they call me to say that they've found the culprit - "the previous owner had wired open the exhaust valves, and it was the attempted actuation of these whilst the car was cold, that was the whining noise". (Paraphrased)

I confess to not being convinced at all, but it had been a month and I wanted my damn car back.

Within half a mile of leaving the dealership, my daughter and I both thought we heard the same noise again, this time with the windows up!

Sure enough, took the car for a drive yesterday, nice and gentle whilst getting up to temp....and it's still there, worse than ever (ambient temps have now dropped here, probably assisting with the audibility of it)

So, here's what I've noticed so far:

Car = cold, engine temp not even at 70
My M preset is set to Gearbox=S3, Steering=Sports, Suspension=Sports, Engine=Sports+
Ambient = 5degsC
Road=dry
Gear=2nd
Off-throttle and coasting down from 20mph to 10mph

I drove for 20mins and about 6miles (slowly of course), and it was evident as soon as I was alongside a building/house/fence, where sound was bounced back.

Managed to catch it on the iPhone, LH F&R windows down and my daughter just aiming the mic at the window aperture. Apologies for video quality.

Most clearly heard at:

4min10s
4min20s
5min10s

But also at:

1min10s
2min07s
3min0s

I went out again this evening with my Father passengering - the first 30-45secs of driving, it's not there, then all of a sudden it's VERY audible; unfortunately I didn't have phone/GoPro with me (I was dropping him home), so couldn't get better recording than the above YouTube clip.

Could you guys take a listen at the following times, and tell me if you have something similar with your cars please? I can't imagine for a second that this is "business as usual", right?

Many thanks
Spencer.

[FANBMWM]

I can hear the squeal clearly. I'm very sorry to hear you have that problem. That can't be normal. I hope they will resolve your problem as soon as possible.

[spenny_b]

Thanks, I'm sure we'll get there.

Unfortunately, BMW seem to have a policy of not being able (allowed?) to solicit an out-of-region dealership to get a heads-up of what the problem could be. I offered to try and reach out to ChrisNich117 and find the dealership he was working with...nope...es ist verboten. BMW GB = different company to BMW NA, simply not going to happen. In addition, no web or forum input will be taken into consideration in terms of investigation or evidence. Unbelievable. Arrogance in extremis.

[TheHouseWon]

Hmm, I have heard similar on mine but thought it was power steering... I hope you get it resolved. I will update this thread with info from my dealership

[13M5F10]

Definitely sounds like the rear differential to me. They they attempt to flush it at least and see if that improved any?

[spenny_b]

Originally Posted by 13M5F10

Definitely sounds like the rear differential to me. They they attempt to flush it at least and see if that improved any?

No idea I'm afraid - not been given a blow-by-blow list of things they've tried, nor any dialogue between them and BMW GB/AG.

Yesterday afternoon I emailed the Sales Manager, Service Mgr and Head Tech with the latest video and an update. No reply as-yet.

Once you hear something, very hard to un-hear it - dropping my daughter to school this morning, I seemed to have tuned into the noise, where I can now hear it pretty much all the time on light throttle. Either that, or the problem's getting worse.

[Andynev1982]

Originally Posted by spenny_b

No idea I'm afraid - not been given a blow-by-blow list of things they've tried, nor any dialogue between them and BMW GB/AG.

Yesterday afternoon I emailed the Sales Manager, Service Mgr and Head Tech with the latest video and an update. No reply as-yet.

Once you hear something, very hard to un-hear it - dropping my daughter to school this morning, I seemed to have tuned into the noise, where I can now hear it pretty much all the time on light throttle. Either that, or the problem's getting worse.

Do you find that the noise disappears once everything warms up? I have the same noise every time I drive off, but it disappears after a mile or two.

I's presumed it was related to rear diff oil getting up to temperature. Could be wrong. Doesn't bother me too much.

[NightM]

Had those noise since after 15k miles. My car now has 28k still whinnying i ended up zoning away from the noise. Lol


Ask m5q8 he found the issue

[DRiFT_645]

I have this same noise. Started about a month ago. About the same time cold weather came. Only happens for about 10-15 minutes when the car is first started.

[TheHouseWon]

In one of his posts, m5q8 said it was a dual mass bearing

[Northern X5M]

Yeah, under slight acceleration at low speed, mine sounds slightly like straight cut gears. I just consider it normal.

[drbru]

this is normal as long as the whine goes away after the car is up to temp....

[Butty45]

This sounds familiar to the sound I got on mine, but mine was coming more from the passenger side but more towards the front wheel.
Does it make the sound if you sit still and rev the car in neutral? can you hear it when revving with the bonnet up? Sometimes it's hard to work out exactly where the sound is "really" coming from.

[spenny_b]

Apologies guys, I set thread alerts to notify me of any replies, but received no emails! Assumed nobody had heard the same noise.

Thanks for the feedback - so it appears more common than I thought. Encouraging that there seems to be no immediate impact of that noise, but on the other hand, with an engineering background and witnessed/chased many squealing bearings/bushes on high end printing systems (fond memories of my apprenticeship!), as well as cocking about with cars for the last 25yrs, no squeak is ever a good sign, and manufacturers don't engineer-in squealing....so on that basis, I'm going to pursue BMW to nail this and resolve.

As an update, one of the guys from my local dealer lives in the same village where my daughter goes to school. Instead of going to the dealership last Thursday, he came over to my house and jumped in the passenger seat to hear it first-hand.

Despite the ambients being up to 10degs, we did still hear the noise, in exactly the same place in town where it's always audible. He heard it clearly a number of times from then back to my house.

He did say that the technicians have at their disposal a multi-channel listening gadget, whereby numerous probes can be clipped onto components or areas of the car, and the relevant channel selected to then listen to each input. That will be their next plan of attack, when I book it back in. Incidentally, his gut reaction was differential as well.

Thanks for the heads-up on the dual mass bearing though (I presume we're talking DM Flywheel?), I'll suggest that to them, and possibly reach out to m5q8 as well.

Keep you posted chaps.

Thanks again
Spencer.

[spenny_b]

Originally Posted by TheHouseWon

In one of his posts, m5q8 said it was a dual mass bearing

Just found his thread, thanks. That (to me) sounds like normal transmission whine....very short clips, so hard to tell, but don't think it's the same noise I'm hearing. Mine's very much on coast-down rather than there-all-the-time acceleration.

Also, I confess to a lack of knowledge on whether the flywheel/release bearing would be the same on a manual vs DCT transmission. (Surely it can't have anything in common?)

[spenny_b]

Originally Posted by Butty45

This sounds familiar to the sound I got on mine, but mine was coming more from the passenger side but more towards the front wheel.
Does it make the sound if you sit still and rev the car in neutral? can you hear it when revving with the bonnet up? Sometimes it's hard to work out exactly where the sound is "really" coming from.

No, it doesn't make the noise while stationary and revving...but in fairness neither have I tried listening to it with bonnet up and revving. Seems to be road speed related rather than engine speed. But, anything's worth a go, only 2secs to test.

[spenny_b]

Originally Posted by Andynev1982

Do you find that the noise disappears once everything warms up? I have the same noise every time I drive off, but it disappears after a mile or two.

I's presumed it was related to rear diff oil getting up to temperature. Could be wrong. Doesn't bother me too much.

Yup, it does disappear once everything is at operating temps. A 400 mile run over the weekend, and only heard it for the first 5mins on the 3 cold starts I did....but ambients were up around 8-12degsC, so not particularly cold.

[TheHouseWon]

Originally Posted by TheHouseWon

Hmm, I have heard similar on mine but thought it was power steering... I hope you get it resolved. I will update this thread with info from my dealership

Mine was confirmed to be the power steering. Shop foreman at the dealership said it is fairly common and only heard when car is cold.

[spenny_b]

Originally Posted by TheHouseWon

Mine was confirmed to be the power steering. Shop foreman at the dealership said it is fairly common and only heard when car is cold.

Thanks THW - very interesting, and for sure I'll mention it to the guys when it goes back in, in a few weeks time. Mine's definitely getting worse, despite very mild ambient temperatures - annoying the hell out of me now, listening to the radio to distract me from it!

[Jhenka]

I believe i have the same issue, and i too started noticing it as the temperatures dropped. It's driving me insane!!! Let me know if any of you guys figure it out. Here's my thread along with videos as well.
http://f10.m5post.com/forums/showthread.php?p=21097371

[v3n0m]

I have the same rear diff squeal everyone's describing. Noticed it today. Accelerate from stop at around 1200 rpm and it happens briefly. Would be interested if anyone identifies an actual problem/resolution.

[spenny_b]

Evening folks,

I had a call from the service dept at my BMW dealership this afternoon, with an update following me leaving it with them on Monday.

It appears they've now identified where the noise is coming from. It's the gearbox. I don't know any more specifics - I would presume that because its road speed and not engine speed related, it's likely to be something on the output shaft (propshaft) end, but this is just my speculation.

Anyway, BMW GB have agreed and signed off on getting a new unit installed. Work is being done at the moment.

I confess, I wasn't expecting it to be the gearbox, and I'm bloody thankful that this is all under warranty. Reinforces my thinking to pay the annual warranty extension, as/when it expires. No amount of rainy-day fund (that I'm likely to accumulate) would cover the cost of replacing the box and the labour.

Needless to say, I'm certainly looking forward to a more thorough chat with their head-tech. If I find out more, I'll post.

Spencer.

ETA - Car had 16.5k miles on when I bought it, and now has a smidge over 21k miles....not exactly a leggy example with an intergalactic history.