BMW M3 Forum (E90 E92)

BMW Garage BMW Meets Register Search Today's Posts Mark Forums Read


Go Back   M3Post - BMW M3 Forum > E90/E92 M3 Technical Topics > Mechanical Maintenance: Break-in / Oil & Fluids / Servicing
 
Post Reply
 
Thread Tools Search this Thread
      10-09-2010, 10:05 PM   #1
stE92M3
New Member
 
Drives: 2008 BMW E92 M3 Coupe
Join Date: Dec 2009
Location: Seattle

Posts: 14
iTrader: (0)

E92 M3 broken differential bolt

Hopefully this is informational if your E9x M3 6MT (or DCT) is making new weird sounds. Sorry for the long article but I wanted to be clear.

This week was somewhat unpleasant. At ~11.5K miles, on last Saturday, the car started to make weird "popping" sounds from the back. The sounds would happen sometime during a shift, after a shift or just decelerating/coasting/engine braking between 2-3K RPM. This was not the usual clutch/flywheel judder/shuddering sound that this performance car is supposed to make.

I took the car in on Tuesday and was unable to duplicate the sound the on a test drive with a chief mechanic at the dealership. After driving the car, they recommend a diff fluid change to some new compound based on some BMW SIB (under warranty). On Tuesday evening, the car seems a lot more smoother to shift/drive. The sound no longer shows up. Diff fluid magic?

Wednesday: Car not driven

Thursday: At the end of a 50 mile trip (with 2 stops), 1 mile away from my garage, the car suddenly makes a loud grinding/metallic/holy-S$!t sound. It is like taking 2 metal garbage can lids and rubbing them against each other at high rotational velocities; coming from the back of the car. Car will shift, drive silently at slow speeds. Scary-ass-transmission-sounds-screwed sound at 2-3K RPM especially when coasting. I though the transmission was a goner.


Friday: I take the car in at 8AM. I haven't seen 8AM in like 6 months! Sound stops on the 1.5 mile drive to the dealership from my home. On a test drive with the shop foreman, unable to duplicate the sound again. WTF - felt like I was losing my mind and hearing things. I leave the car with the foreman and let him drive it all day while I was at work. On the 4th drive, (he seemed to have driven the car 10-15 miles that day), he was able to make the car make that sound after a hard turn.

After raising the car on the lift, they notice that the left hand side differential bolt has broken through clean:

http://www.realoem.com/bmw/showparts...=33&fg=05&hl=4

(Part M12X100-10.9 on the left hand side)

According to the techs/shop foreman: either the bolt was torqued incorrectly or the metal was bad(das german engineering quality control?). They even showed me the broken bolt later when I picked up the car (much appreciated).

The diff bolt was replaced after removing and remounting the diff, torquing everything back there correctly. They overnighted the part (2 dollar bolt!) and I had the car on Saturday afternoon. Quick!

As a side effect, the "judder"/shudder, 2nd gear notchy feeling and occasional feeling of shifts/clutch not being smooth have gone away. The clutch feels a lot lighter, the shift sounds are almost gone. The car feels new and different and just smooth overall! The dealership seems to have done an awesome job, took the time to explain things to me. It seems all the other parts around are not damaged due to the broken bolt. Time will tell.

It seems some other E9x owners and some E46 owners have had differential mounting bolt issues. Sucks but I guess its a performance car and stuff breaks.
__________________
-
T

2008 BMW M3 Coupe / 6MT / Tech / Cold / Premium / EP Sound / iPod:USB / PDC
stE92M3 is offline   United_States
0
Reply With Quote
      10-09-2010, 10:48 PM   #2
elp_jc
Brigadier General
 
Drives: .
Join Date: May 2008
Location: .

Posts: 4,910
iTrader: (0)

Hey man, glad your problem was corrected, but that bolt (#2) you mentioned just supports the exhaust, not the differential . Maybe bolt #4, which is a beefier M14. At any rate, that's weird man. Have you tracked your car?
elp_jc is offline   United_States
0
Reply With Quote
      10-09-2010, 10:56 PM   #3
stE92M3
New Member
 
Drives: 2008 BMW E92 M3 Coupe
Join Date: Dec 2009
Location: Seattle

Posts: 14
iTrader: (0)

Thanks. To be more clear:
Bolt #3 on the car's left hand side (not diagram's letf) broke and the diagram shows it mounts to the diff. It actually caused the diff to move a little causing more noise. It mounts the diff to some part of the car( perhaps connecting it to some part of the exhaust system). Part number: 33176760343 (Hex bolt with Washer). The invoice also calls it "LOWER DIFF BOLT" (and matches up with the part number #3 in the diagram). Yes it is a pretty beefy looking bolt so it was somewhat worrisome it broke.
__________________
-
T

2008 BMW M3 Coupe / 6MT / Tech / Cold / Premium / EP Sound / iPod:USB / PDC
stE92M3 is offline   United_States
0
Reply With Quote
      10-10-2010, 04:55 PM   #4
elp_jc
Brigadier General
 
Drives: .
Join Date: May 2008
Location: .

Posts: 4,910
iTrader: (0)

Quote:
Originally Posted by stE92M3 View Post
Bolt #3 on the car's left hand side (not diagram's letf) broke
Bolts #2 and #3 are identical, and all they do is support the exhaust pipe brackets (left and right) to the differential, so don't worry; it's nothing serious. The orange hangers attach to those brackets and the exhaust pipes. The bracket was just making a racket against the differential (or pipe possibly touching driveshaft), but it's definitely not the differential itself. It's weird that the bolt just broke when there's little stress on it. Glad it wasn't a more important bolt.
elp_jc is offline   United_States
0
Reply With Quote
      10-22-2010, 11:56 AM   #5
KJM3
Private First Class
 
Drives: 2011 E92 M3 6MT
Join Date: Sep 2010
Location: East Tennessee

Posts: 177
iTrader: (0)

Quote:
Originally Posted by elp_jc View Post
Bolts #2 and #3 are identical, and all they do is support the exhaust pipe brackets (left and right) to the differential, so don't worry; it's nothing serious. The orange hangers attach to those brackets and the exhaust pipes. The bracket was just making a racket against the differential (or pipe possibly touching driveshaft), but it's definitely not the differential itself. It's weird that the bolt just broke when there's little stress on it. Glad it wasn't a more important bolt.
Actually no.

The two front bolts that go through the exhaust hangers also go through the rubber isolated mounts on the crossmember.

There are only three bolts holding the differential on, two smaller diameter in the front and one larger one on the rear. I am under the car right now looking at it
KJM3 is offline  
0
Reply With Quote
      10-22-2010, 02:03 PM   #6
Hbenz
Private
 
Hbenz's Avatar
 
Drives: 09' E92 M3 AW
Join Date: May 2009
Location: Toronto

Posts: 80
iTrader: (0)

I've had this same Issue, except I had some transmission damage occur from it and they replaced the bolt + transmission
Hbenz is offline   Canada
0
Reply With Quote
      10-23-2010, 12:10 AM   #7
roller
Private First Class
 
roller's Avatar
 
Drives: E92
Join Date: Jun 2009
Location: OC, CA

Posts: 164
iTrader: (0)

Dang.. I hope this doesn't become a widespread issue.
roller is offline  
0
Reply With Quote
      10-29-2010, 06:46 PM   #8
JETonFOX
New Member
 
Drives: 2011 E93 CONVERTIBLE
Join Date: Jun 2010
Location: NY

Posts: 11
iTrader: (0)

I Am Having This Issue Rite Now, Roadside Is On There Way....how Long Did It Take To Fix?.........btw Was The Noise You Were Hearing After Shift Like A Loud Banging Noise ( Almost Sounds Like The Back End Is About To Come Rite Off)
Please Reply Asap Im Freakin Out
JETonFOX is offline  
0
Reply With Quote
      10-29-2010, 07:38 PM   #9
Dntlvet
Dntlvet
 
Dntlvet's Avatar
 
Drives: 10 M3 Sedan,13 GT-R BE,13 Pors
Join Date: Jul 2009
Location: Wisconsin

Posts: 448
iTrader: (0)

Wow, this thread is spooky scary.
My car has 9K miles.
Should I have the dealership check for these bolts?
Dntlvet is offline   United_States
0
Reply With Quote
      10-29-2010, 08:23 PM   #10
bobbyd1961
Banned
 
Drives: 2009 M3 sedan LeMans Blue
Join Date: Jun 2009
Location: new jersey

Posts: 2,411
iTrader: (0)

does the sound come from the back of the car during a hard acceleration? becasue that has happened to me almost like a bang ( not a backfire ) like a bolt being hit with a hammer?
bobbyd1961 is offline  
0
Reply With Quote
      10-29-2010, 09:04 PM   #11
JETonFOX
New Member
 
Drives: 2011 E93 CONVERTIBLE
Join Date: Jun 2010
Location: NY

Posts: 11
iTrader: (0)

yeah a very loud bang....i also heard a very loud grinding noise so i pulled over and had it towed

lets see what the dealer says in the AM
JETonFOX is offline  
0
Reply With Quote
      10-29-2010, 11:34 PM   #12
elp_jc
Brigadier General
 
Drives: .
Join Date: May 2008
Location: .

Posts: 4,910
iTrader: (0)

Quote:
Originally Posted by KJM3 View Post
There are only three bolts holding the differential on, two smaller diameter in the front and one larger one on the left rear. I am under the car right now looking at it
I stand corrected. Got under the car too, and that's indeed the case.

Man, I don't doubt these cases, but shearing a bolt that thick with surfaces next to each other is unheard of, especially with a differential. Have you guys done any launches? Could somebody post pictures? Wonder if we should replace ours as a precaution . Or is it abuse? It still shouldn't happen though; usually shaft splines are the weak link.

Last edited by elp_jc; 05-18-2011 at 12:14 AM.
elp_jc is offline   United_States
0
Reply With Quote
      10-31-2010, 04:35 PM   #13
stE92M3
New Member
 
Drives: 2008 BMW E92 M3 Coupe
Join Date: Dec 2009
Location: Seattle

Posts: 14
iTrader: (0)

Quote:
Originally Posted by JETonFOX View Post
yeah a very loud bang....i also heard a very loud grinding noise so i pulled over and had it towed

lets see what the dealer says in the AM
I didnt hear a loud bang, just telltale "pop"ing sounds before it gave way to the grinding. Good luck with your fix.
__________________
-
T

2008 BMW M3 Coupe / 6MT / Tech / Cold / Premium / EP Sound / iPod:USB / PDC
stE92M3 is offline   United_States
0
Reply With Quote
      11-01-2010, 03:18 AM   #14
dvpouldar26
Major
 
dvpouldar26's Avatar
 
Drives: 2008 e92 328i, Porsche 987.1
Join Date: May 2008
Location: Beverly Hills, CA

Posts: 1,464
iTrader: (4)

My friend had this problem in hi e9x m3 with 6mt. Its been said that these e9x m3's are nowhere near as stout to take the abuse as the e46's. Upon taking the car to Sam@Autotalent, he said this has happened to a few of his clients already. The bolt has to be ordered from Germany and the bracket could also get easily damaged. In my friend's car, he has repeated launches, and upon many many WOT runs, shifted hard and fast. The weight transfer made the bolt go out. Sam also said his subframe was slightly tweaked. This problem is happening to mostly 6mt owners apparently. A clunk noise could be heard, and the dealer will not back up the damage because of repetitive launches or mods. It is easier to take it to an independent service shop.
__________________
E92 328i
Jet Black / Gloss Black Grilles / 8000k D1S low beam / 6000k HID fogs / GP Thunder 8500k angels & cornering bulbs / black reflectors / gloss black vinyled window trim / tints / smoked rear turn signals / black roundels / AC Schnitzer roof spoiler / VRS style decklid spoiler / Matte black Stripes / Rear fogs / matte mirrors / 19" LM reps / APR lip
dvpouldar26 is offline  
0
Reply With Quote
      05-17-2011, 03:47 PM   #15
Dustin@AEp
Captain
 
Drives: BMW E92 M3
Join Date: Mar 2010
Location: Southern California

Posts: 625
iTrader: (2)

Send a message via AIM to Dustin@AEp
This has happened to me already and they replaced the bolt under warranty...and after 5k miles, I have another broken bolt. Woo Hoo!

Off to the dealership
Dustin@AEp is offline   United_States
0
Reply With Quote
      05-21-2011, 12:10 AM   #16
elp_jc
Brigadier General
 
Drives: .
Join Date: May 2008
Location: .

Posts: 4,910
iTrader: (0)

Quote:
Originally Posted by Dustin@AEperformance View Post
This has happened to me already and they replaced the bolt under warranty...and after 5k miles, I have another broken bolt. Woo Hoo!
Man, that's the first time I ever hear of bolts of that size just shearing off . Are those bolts TTY? Have you drag-raced your car? Just can't imagine what could be putting the kind of stress to shear a bolt off like that. Thanks for the update.
elp_jc is offline   United_States
0
Reply With Quote
      08-22-2011, 02:32 AM   #17
Rac3rX
Racer X
 
Rac3rX's Avatar
 
Drives: 2011.5 iB E90 6MT
Join Date: Mar 2008
Location: Bakersfield

Posts: 226
iTrader: (4)

this has also happened to me twice! and the car only has 5K miles first it was the exhaust bolt and then less then 1K miles later the diff bolt. witch made the diff fall and bent the rear subframe. would this pass for a lemon law if it happens again? i really dont feal safe in this car. and my 2 y.o. daughter is with me 98% of the time and now i dont even want to take her in the car! this is somthing that should not be happening with a 70K car!
__________________
2011.5 iB E90 M3 6MT

08 E92 335i12.1 @ 118MPH Gone
Rac3rX is offline   United_States
0
Reply With Quote
      08-22-2011, 09:33 AM   #18
Singletrack
4th down; 4th quarter? Renegade.
 
Singletrack's Avatar
 
Drives: 09 SSII E92 M3; 12 AW X5d
Join Date: Aug 2008
Location: Pittsburgh, PA

Posts: 3,795
iTrader: (3)

This definitely appears to be a trend.
Singletrack is offline   United_States
0
Reply With Quote
      08-22-2011, 11:04 AM   #19
Ilia@IND
BimmerPost Supporting Vendor

 
Ilia@IND's Avatar
 
Drives: F10 M5
Join Date: Oct 2006
Location: Chicago

Posts: 2,163
iTrader: (3)

I can't imagine that these fastners are torque to yield fastners. The bolt isn't even loaded in tension like a head bolt, but in double shear. I wonder if it's shearing more from vibration than from actual constant load.
__________________
Ilia@IND is offline  
0
Reply With Quote
      08-22-2011, 05:08 PM   #20
elp_jc
Brigadier General
 
Drives: .
Join Date: May 2008
Location: .

Posts: 4,910
iTrader: (0)

Quote:
Originally Posted by Ilia@IND View Post
I wonder if it's shearing more from vibration than from actual constant load.
They're rubber-mounted, so I'd say that is extremely unlikely. It could happen, but only on a defective bolt IMO, not as a root cause by itself. I'd also rule out excessive torque, as you'd need a crapload more than normal to cause tensile failure on such a big a$$ bolt. Unfortunately, I don't expect posters to tell us the truth for fear of BMW/dealers reading this forum and denying warranty, so we have to take those posts with a grain of salt (understandable). Here are the most likely causes IMO:

- Owner abuse in the form of axle-hop, repeated launches, etc.
- Missing or loose bolts from an exhaust installation
- Bad aftermarket spring job, where installer uses diff/sub-frame as lever to remove/install springs.
- lifting and leaving car raised from the differential for long periods of time
- Road hazards, like big potholes, hitting a curb, etc.
- Defective bolts (very unlikely IMO).

Defective bolts are a possibility, but I could bet cash money there were at least one of the other factors mentioned above in each of those cases. But again, we'll never know here (unfortunately) for fear of self-incrimination. Checking one of the severed bolts would quickly put prove that theory or put it to rest. If defective, it'd be an immediate recall, and it's something quite cheap to fix, so I don't see BMW playing games with that.

I wouldn't consider this car unsafe Rac3rX. If you believe everything on the internet, you'd be paranoid by now . Enjoy your car man. If you don't abuse your car, there's nothing to worry about IMO. Yes, I'll keep an eye on these threads, but am not concerned about this at all since I never abuse my car, and always drive it mostly alone. Good day.
elp_jc is offline   United_States
0
Reply With Quote
      08-22-2011, 05:39 PM   #21
PhillyNate
ENTHUSIAST
 
PhillyNate's Avatar
 
Drives: 2014 Toyota GT-86
Join Date: Apr 2011
Location: Philadelphia

Posts: 2,027
iTrader: (0)

Garage List
I'm with elp_ jc. Thanks
__________________

"what I'm driving here...is an ending." Jeremy Clarkson
2014 Whiteout Toyota GT-86 6mt(Presently enjoying WAY more than anticipated)
2011 Alpine White BMW M3 6mt ZCP Coupe(forced retirement 06/06/14)
2008 Alpine White BMW 328i 6mt Coupe(retired 06/21/11
)
PhillyNate is offline   United_States
0
Reply With Quote
      08-22-2011, 05:55 PM   #22
stega
Captain
 
Drives: 2011 M3 E93
Join Date: Nov 2010
Location: Boca Raton, FL

Posts: 666
iTrader: (3)

Using the diff as a jack point should not cause this as some others have said...
stega is offline  
0
Reply With Quote
Post Reply

Bookmarks

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump


All times are GMT -5. The time now is 04:18 PM.




m3post
Powered by vBulletin® Version 3.7.0
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
1Addicts.com, BIMMERPOST.com, E90Post.com, F30Post.com, M3Post.com, ZPost.com, 5Post.com, 6Post.com, 7Post.com, XBimmers.com logo and trademark are properties of BIMMERPOST