[DETRoadster]

Originally Posted by Johnsonuspp

If the mesh shields work can you post a link so we all can share in the fix.

Yes, this. Let's see what those mesh shields look like. I pulled my rear wheel off and poked around the dust shield. There's really no obvious place to affix the shield. if anyone has a mesh shield installed I'd sure love to see it. I guess I was envisioning an air inlet scoop of some sort on the dust shield. Some obvious place that calls out for being covered. But there simply isnt. I'm thinking that bending the backing plate back is probably the best course of action.

[MRufo]

Mine is a 2017 and I have 4 noises, thumps, vibrations and screeches happening. There is definitely something going on when going slowly up a steep hill getting on and off the throttle.
Just checked mybmw today and no recalls yet.

[CosmosMpower]

Get your parking brake adjusted.

[NOLAGUY]

Originally Posted by MRufo

Mine is a 2017 and I have 4 noises, thumps, vibrations and screeches happening. There is definitely something going on when going slowly up a steep hill getting on and off the throttle.
Just checked mybmw today and no recalls yet.

I had the scraping sound again this morning. It's always over a sharp/steep bump.

[highspeed]

Originally Posted by NOLAGUY

Do the 2017s have any known rear differential issues? I have a 17 and over the weekend I was going slowly up a steep driveway and I heard something that sounded like I scraped the ground. It happened 3 times in total.

I have exactly the same noise on my one
It sounds like scratching over the ground or having snow between tires and wheel housing.

It has the DCT and was build in week 51 of 2016. I drove him about 750km until now and my run-in driving is very gentle with no reving over 3500rpm and just giving half throttle.
The actual outside temperatures are about -10°C.

I can replicate the noise - mostly in the 4th gear at about 2000rpm - and it also comes in Sport mode.

If this is really a noise caused because of the low temperature, all would be fine ... nevertheless it's really annoying.

[Artemis]

Originally Posted by pruettfan

Lots of panic over rear diff noises. We need to understand that there is a electronically controlled clutch in the diff that activates as driving conditions warrant the need for power to be put a different drive wheel. These diffs will make some noise, they are not like a conventional differential so comparing it to what you have experienced in the past is not relevant. These differentials have been used in the M5, M6, M3 and M4 for years and you will be hard pressed to find many actual issues with them beyond the recall that they initiated proactively. When you understand how this differential works it is easier to understand how it will make some noise from time to time.

Never heard the 'soda can crunch' sound on my previous car (1M). But, true, it got different wheels and diff design.

[ried]

I honestly cannot believe anyone still questions whether or not it's the differential.

It's not.

There have been no reports of a diff making the "soda can crunch" noise for a reason other than rocks in the brake shield. Yes, it sounds terrible. Yes, it's sounds like a crunch, or metal-on-metal scrape, and yes it can happen several times in rapid succession or it might happen once in a great while. It does go away over time, especially if you flex the shield to give any rocks that might get lodged in there more clearance to fall out. There's no way to reliably reproduce the phenomenon, and it's somewhat alarming when it does happen.

But it's completely benign, will not hurt your car, and none of this should be conflated with the old diff recall that affected early MY '16 vehicles.

[Kapachui]

agreed. sounds like rocks between the brake shield and rotor.

[le panecito]

Originally Posted by NOLAGUY

I had the scraping sound again this morning. It's always over a sharp/steep bump.

Mine does the same thing. It doesn't happen always, but I hear it when pulling up a driveway or slowly turning onto a street.

[NOLAGUY]

I found a driveway to replicate the crunching sound. It's very repeatable on steep roads. But it's not the diff or rocks in the dust shield. It's when one rear tire has nearly no weight on it. The tire does a mini burnout. Almost half a rotation before transferring power.

Odd part is I'm going 1-2 mph

[DETRoadster]

Originally Posted by NOLAGUY

I found a driveway to replicate the crunching sound. It's very repeatable on steep roads. But it's not the diff or rocks in the dust shield. It's when one rear tire has nearly no weight on it. The tire does a mini burnout. Almost half a rotation before transferring power.

Odd part is I'm going 1-2 mph

Get some video for us! Or post a pic of the car on the driveway. Are you going up, down, at an angle? Not sure how you are getting one wheel unloaded just by going on a steep grade. Pics or a video would be super helpful here.

[NOLAGUY]

I'm going up at an angle. I'll do it again next time I go to my sister's house. Her driveway perfectly repeats this tire slip.

[akkando]

I can reproduce the can crush sound on inclines. MY17 DCT about 700 miles on it. Seems to happen only in Sport + mode I think....

Two video I took tonight of the sound, one going uphill, one going downhill. Sorry for the camera work I was just trying to get the sound. On the downhill looks like I was in 2nd and took my foot off the gas before it happened.

I assume this sound is what other people are hearing?

[M3 Adjuster]

Originally Posted by akkando

I can reproduce the can crush sound on inclines. MY17 DCT about 700 miles on it. Seems to happen only in Sport + mode I think....

Two video I took tonight of the sound, one going uphill, one going downhill. Sorry for the camera work I was just trying to get the sound. On the downhill looks like I was in 2nd and took my foot off the gas before it happened.

I assume this sound is what other people are hearing?

wow. Truly the first time I've actually listened for this sound. DUUUDDE!! That's Fucked up right ?

That's not the rock between the rotor and guard noise at all.


Is there any resistance in the chassis when this happens ? Someone mentioned the car lifting up at the rear ?

Omg if my car had this I think I would make the dealer service rep ride in the car and listen until they scream MAKE IT STOP! and throw the keys to a loaner while they call BMW about a new DIFF.. yikes.

[M3 Adjuster]

Originally Posted by NOLAGUY

I'm going up at an angle. I'll do it again next time I go to my sister's house. Her driveway perfectly repeats this tire slip.

There's definitely some slippage on some subdivision lips as you go up a driveway.. and a short amount of time to transfer to the other wheel is going to also be normal.

Now then if the diff is making a noise like akkando then , I'm no mechanical engineer, but it sounds like a clutch pack responsible for lockup in the differential is chattering ? The M diff definitely can do some funky things ..seeing as its all electronic and hydraulics and all. Wonder if a servo is wigging out ...

[NOLAGUY]

Originally Posted by M3 Adjuster

There's definitely some slippage on some subdivision lips as you go up a driveway.. and a short amount of time to transfer to the other wheel is going to also be normal.

Now then if the diff is making a noise like akkando then , I'm no mechanical engineer, but it sounds like a clutch pack responsible for lockup in the differential is chattering ? The M diff definitely can do some funky things ..seeing as its all electronic and hydraulics and all. Wonder if a servo is wigging out ...

I think my tire slip and sounds are normal, now that I know what it's doing. I am an engineer and I can tell you akkido sounds are pretty fucked up.

[blackholescion]

Mine sounds like that but it's much shorter. It also only seems to happen on roads with rocks or debris. If you take that vid and cut the sound after the first instance before it starts the actual chatter, that's what mine sounds like. Less than 1 second of noise.

I'm now wondering if this isn't just rocks/debris and is the diff.

[DETRoadster]

Originally Posted by akkando

I can reproduce the can crush sound on inclines. MY17 DCT about 700 miles on it. Seems to happen only in Sport + mode I think....

Two video I took tonight of the sound, one going uphill, one going downhill. Sorry for the camera work I was just trying to get the sound. On the downhill looks like I was in 2nd and took my foot off the gas before it happened.

I assume this sound is what other people are hearing?

Holy Hell! Finally!!!! That is the EXACT noise I'm hearing. As I mentioned previously, I have also heard that noise accompanied by a screech (like a clutch pack slipping) and the rear right of the car hopping up.

I'm going to try mine today in the parking garage at work. It's also a slight incline like in your video.

BTW, can you please post these in the "Soda Can Crunch" thread as well? This is by far the best video/audio of the issue anyone has managed to capture. Nice work!!!!

[ried]

Originally Posted by akkando

I assume this sound is what other people are hearing?

13-14 seconds into the second video is the soda can crunch noise. Rocks in your brake shield, dude.

The other, quieter sounds are unrelated.

[akkando]

Originally Posted by ried

13-14 seconds into the second video is the soda can crunch noise. Rocks in your brake shield, dude.

The other, quieter sounds are unrelated.

I can only hear rocks in my brake shield when in sport + mode? Seems fishy to me. Seems like when the rear wheels are allowed to slip more, then it's more likely to happen. It also seems like it's more likely to happen when the car is cold because so far I can't as easily reproduce if it's been driven for more than ten minutes. That's my experience so far anyway.

[King_Slayer]

GJ on the videos I couldn't help but laugh by your comments at the end of them. Hopefully we can figure out wtf that is for sure and not just assume every sound people hear is rocks On the brake shield.

[reddemon]

DEFINITELY not stone in rotor shield or whatever.
i put $1000 on it.who dares take the challenge?