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      01-17-2017, 01:21 PM   #23
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Quote:
Originally Posted by chris719 View Post
OP's issue sounds like the rocks in the brake shield.

x2.
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      01-17-2017, 01:37 PM   #24
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Are these 'rocks' in the brake shield common? I have just noticed as of today that when in reverse and the first brake there is a crunch and then its fine. I have not heard any noise when braking after moving forward... yet.
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      01-17-2017, 01:42 PM   #25
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Actually to add to this when it was quite cold the other day, around -30C I fully warmed up the car and did some 'break in' pulls. 2, 3 and 4th kind of stuff never full load and under 5500rpm and did some braking from various speeds to help bed etc... anyway point being after 5 minutes of that I heard a winding noise metallic in nature underneath the car just behind me when I would accelerate it would wind up and naturally decelerate it would wind down. It was very odd and it had not done it before. i took it in the next day but it had warmed up to -10c and wasn't doing it anymore. dealership put it on the hoist and checked everything out and took it for a test drive and couldn't duplicate the noise. tech guessed that it was a hanger underneath the car but as they couldn't duplicate it got a 'nothing wrong clean bill of health' and i gave the 335 back and left.
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      01-17-2017, 01:49 PM   #26
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Quote:
Originally Posted by quikM2 View Post
Are these 'rocks' in the brake shield common? I have just noticed as of today that when in reverse and the first brake there is a crunch and then its fine. I have not heard any noise when braking after moving forward... yet.
Yep, pretty common.

Quote:
Originally Posted by quikM2 View Post
Actually to add to this when it was quite cold the other day, around -30C I fully warmed up the car and did some 'break in' pulls. 2, 3 and 4th kind of stuff never full load and under 5500rpm and did some braking from various speeds to help bed etc... anyway point being after 5 minutes of that I heard a winding noise metallic in nature underneath the car just behind me when I would accelerate it would wind up and naturally decelerate it would wind down. It was very odd and it had not done it before. i took it in the next day but it had warmed up to -10c and wasn't doing it anymore. dealership put it on the hoist and checked everything out and took it for a test drive and couldn't duplicate the noise. tech guessed that it was a hanger underneath the car but as they couldn't duplicate it got a 'nothing wrong clean bill of health' and i gave the 335 back and left.
Same. Anything below -15C or so and the rear diff gets sluggish and noisy. Once it warms up its ok.
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      01-17-2017, 02:21 PM   #27
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I've got a 17 (took delivery 1 month ago), and I've definitely heard what I would describe as the "can crunching" noise on multiple occasions. No odd performance to report though aside from the sound
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      01-17-2017, 02:48 PM   #28
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Quote:
Originally Posted by ried View Post
x2.
I couldn't get it to repeat during lunch. But I'm sure it wasn't just a rock stuck in the brake shield. I'll have to find a steep curb to replicate the concern.
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      01-17-2017, 03:09 PM   #29
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Quote:
Originally Posted by gmzanatta View Post
Same. Anything below -15C or so and the rear diff gets sluggish and noisy. Once it warms up its ok.
thats the thing, I was driving for half an hour nice and easy and let everything 'warm' up to temp and it still did it. Although perhaps in -35C it can't actually ever 'warm' up.
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      01-17-2017, 03:11 PM   #30
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Quote:
Originally Posted by quikM2 View Post
Quote:
Originally Posted by gmzanatta View Post
Same. Anything below -15C or so and the rear diff gets sluggish and noisy. Once it warms up its ok.
thats the thing, I was driving for half an hour nice and easy and let everything 'warm' up to temp and it still did it. Although perhaps in -35C it can't actually ever 'warm' up.
For me usually after 5km or so it's perfectly fine and it goes away FWIW
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      01-17-2017, 03:15 PM   #31
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Quote:
Originally Posted by gmzanatta View Post
For me usually after 5km or so it's perfectly fine and it goes away FWIW
Good to know. I still only have 700km's on the car.
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      01-17-2017, 03:15 PM   #32
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Quote:
Originally Posted by quikM2 View Post
Quote:
Originally Posted by gmzanatta View Post
For me usually after 5km or so it's perfectly fine and it goes away FWIW
Good to know. I still only have 700km's on the car.
Ah ok - the diff break in oil is very heavy, so it would be even more viscous at low temps, which could be why you're seeing this.
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      01-17-2017, 03:36 PM   #33
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Quote:
Originally Posted by DETRoadster View Post
Mofomat, I'm interested in understanding whether you feel like there's considerable drivetrain slop in your car as well, seeing as how we have both experienced the "hop". I've noticed when I am at light cruise or light acceleration, then lift the gas pedal, I get a little "knock" from the back end. Thought it was slop in the driveshaft u-joints, but perhaps it's differential gears with too much clearance loading and unloading.
I haven't noticed that to be honest, but I'll listen out for it next time I drive the car.
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      01-17-2017, 03:53 PM   #34
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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.
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      01-17-2017, 04:01 PM   #35
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Quote:
Originally Posted by pruettfan View Post
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.
I agreed with you up until the point where the ass end of my car lifted. If you can explain to me how that happens during the normal operation of the car, I'd love understand. Not trying to be sarcastic here. If this sort of occurrence can be chocked up to "normal" diff function I'd really like to understand more.

Last edited by DETRoadster; 01-17-2017 at 04:53 PM..
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      01-17-2017, 08:12 PM   #36
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Quote:
Originally Posted by reppucci View Post
Quote:
Originally Posted by DETRoadster View Post
Mofomat, I'm interested in understanding whether you feel like there's considerable drivetrain slop in your car as well, seeing as how we have both experienced the "hop". I've noticed when I am at light cruise or light acceleration, then lift the gas pedal, I get a little "knock" from the back end. Thought it was slop in the driveshaft u-joints, but perhaps it's differential gears with too much clearance loading and unloading.
I had/"have" this! Like you couldn't tell if u-joint diff, load/unload or perhaps diff housing bushings. Only happens under light load and when changing gears slowly so the rpm match kicks off. I have a 6MT. A knock from the rear of the car.

My diff was replaced under the recall last month (early December). I was going to check if I still had the "slop" after the diff was changed. I only drove her 2-3 times after diff replacement before I put away for the winter. I can't swear to it but I have a vague recollection the slop was still present suggesting u-bolt and not diff related.

When I take her out again after the winter, or if a long warm spell, I will update you.
Exactly what I'm currently experiencing. Subscribed and may be going to the dealership soon if it gets worse. Something feels loose back there. I'm at 1400 miles, but started experiencing it when I picked up the car at PCD. I thought it might be one of those things that would "settle", but it hasn't. I've now altered my shifting technique to avoid it, but still get it under low load drop of the accelerator pedal.
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      01-19-2017, 07:05 AM   #37
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Garage List
2008 BMW 135i  [8.66]
This is what is says in the owner's manual regarding the drivetrain.
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      01-19-2017, 07:24 AM   #38
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GUYS GUYS GUYS GUYS!!!!! 95% of all this here are the small rocks in the sheilds. Get some mesh covers and be done with it. Im 7k miles deep and that issues was solved many many moons ago by now. M4's have same issue. Its giant wheels sticky rubber and open brakes catch debris at will.
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      01-19-2017, 08:10 AM   #39
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Quote:
Originally Posted by RPM2-85 View Post
GUYS GUYS GUYS GUYS!!!!! 95% of all this here are the small rocks in the sheilds. Get some mesh covers and be done with it. Im 7k miles deep and that issues was solved many many moons ago by now. M4's have same issue. Its giant wheels sticky rubber and open brakes catch debris at will.
I'm open to the idea and have some stainless steel mesh on order. Ill report back as to whether it did the trick.
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      01-19-2017, 08:20 AM   #40
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If the mesh shields work can you post a link so we all can share in the fix.
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      01-19-2017, 08:40 AM   #41
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Quote:
Originally Posted by RPM2-85 View Post
GUYS GUYS GUYS GUYS!!!!! 95% of all this here are the small rocks in the sheilds. Get some mesh covers and be done with it. Im 7k miles deep and that issues was solved many many moons ago by now. M4's have same issue. Its giant wheels sticky rubber and open brakes catch debris at will.
The rocks are a different noise and they definitely will not lift the back end of the car like one of the above posters described.

The rocks is more of a screeching/grinding noise.
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      01-19-2017, 08:32 PM   #42
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Quote:
Originally Posted by gmzanatta View Post
Quote:
Originally Posted by RPM2-85 View Post
GUYS GUYS GUYS GUYS!!!!! 95% of all this here are the small rocks in the sheilds. Get some mesh covers and be done with it. Im 7k miles deep and that issues was solved many many moons ago by now. M4's have same issue. Its giant wheels sticky rubber and open brakes catch debris at will.
The rocks are a different noise and they definitely will not lift the back end of the car like one of the above posters described.

The rocks is more of a screeching/grinding noise.
Yup agreed. Two different noises. I couldn't care less about the screeching/rocks right now. But the clunky diff or drive shaft??? Is starting to worry me. It's definitely getting worse. I just came from an F80 M3 and didn't have this sound. Never had a car with such "play" or clunk.

I'd take it to the dealer but I'm not interested in people beating the car around to replicate. I will give it some time and see if it gets worse. One thing is for sure, it's annoying as hell. Today I was in comfort mode for a lengthy phone conversation and it was worse in comfort, which I suspect is due to less load.
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      01-19-2017, 08:35 PM   #43
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Quote:
Originally Posted by DTNJNQ View Post
This is what is says in the owner's manual regarding the drivetrain.
If only it was a click... this is more clunky, as if something is loose or has too much play.

The good news is that if you apply lots of torque to things that have give/play, they will eventually snap.

So time will tell!
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      01-20-2017, 03:56 PM   #44
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My car has these noises that everybody is talking about here. I'm still under 300 miles on my car and been to the dealer numerous times for "Check Engine" light coming on every 50miles and to check the noises issue. They can't figure out either issue!!!!

For one, the they're unable to duplicate the noises since they come and go. As far as the "check engine" light issue; they're telling me that I need a new "Crank Case" but before they do the repair, they need to consult with Germany. I've had a loaner for a week now and no end in sight. The tech told me that my new car is being used as a guinea pig; I said WHAT???

I'm extremely angry....
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