09-07-2020, 04:26 PM | #1 |
Private First Class
165
Rep 171
Posts |
Clunk from real diff?
I had a great drive this afternoon, but I noticed a clunking noise when down shifting towards the end of my 2hr drive. (6 spd Manual) Seems like it comes from the rear diff. And it occurs when I lift off of the clutch after a down shift with some engine braking. I searched the internet and I came across people who reported the same "thing", but no solid tech answer as to why it occurs. Is it a symptom of a mechanical problem? Definitely has me concerned
|
09-07-2020, 11:22 PM | #2 | |
Captain
210
Rep 959
Posts |
Quote:
__________________
|
|
Appreciate
1
Mavallone164.50 |
09-08-2020, 01:22 AM | #4 | ||
Private First Class
165
Rep 171
Posts |
Quote:
|
||
Appreciate
0
|
09-08-2020, 01:27 AM | #5 |
Private First Class
165
Rep 171
Posts |
Poochie - I was hoping you would take the case! My concern is that it feels like slack in the drive train. Not sure that's a good thing. I did find this however in the owners manual, what BMW refers to as clicking, is more of a clunk that I feel.
|
09-08-2020, 01:33 AM | #6 |
Brigadier General
2088
Rep 3,006
Posts |
M2 or M2C?
There were a few M2s early on that had a problem with the diff bracket bolt. Sorry, can't find a link. My M2 would sometimes have a clunk when pulling out. I think it was slop before the diff engagement? Here's a thread of various complaints. https://f87.bimmerpost.com/forums/sh....php?t=1344418 Or like Poochie said could be the locking diff. There was also a stop sale but those cars should have been fixed. https://static.nhtsa.gov/odi/tsbs/20...47013-9999.pdf |
Appreciate
1
Mavallone164.50 |
09-08-2020, 05:15 AM | #7 |
Private First Class
165
Rep 171
Posts |
Omasou - thank you for the feedback
M2C, just picked it up last week only a few hundred miles on the clock. Drove to the train this morning in efficient and all was quiet, 3rd to 2nd downshifts, even with engine braking caused no clunk. After work I will experiment with sport and Sport Plus. |
Appreciate
0
|
09-08-2020, 11:28 AM | #10 | |
Brigadier General
2088
Rep 3,006
Posts |
Quote:
Not sure about OP but the best way to describe my sound was...imagine a circle with a notch cut out of the interior...then imagine a rod keyed to fit the inner circle and notch...when you turn the rod the outer circle spins. In my case it sounded like the key had space around it and when I pulled out the rod rotated, slapped the inside of the notch making a clunk sound and then was quiet. This mostly happened from a dead stop but also sometimes when I lifted and reapplied the gas. Hope that makes sense. Might be the diff locking/unlocking but sound was intermittent. Some talked about a bad diff bracket bolt, which for some reason there is only one, see Real OEM. I could imagine a similar sound would happen, if that bracket is not tight to the body. I think it. is part #2 or #7 https://www.realoem.com/bmw/enUS/sho...diagId=33_1838 Last edited by omasou; 09-08-2020 at 02:01 PM.. |
|
Appreciate
2
Mavallone164.50 QuarterMileJoe9.00 |
09-08-2020, 11:34 AM | #11 | |
Luxury at the redline :)
9105
Rep 7,563
Posts |
Quote:
As I mention, the M LSDs, the crown-jewel of the model, tends to be noisy. That combined with the lack of sound insulation, gives the driver a more "raw" aural feedback. Check out the video below, one of favorite automotive reviewers mention this at 6:10, as a point of contention: |
|
Appreciate
1
QuarterMileJoe9.00 |
09-08-2020, 01:31 PM | #12 |
Captain
1640
Rep 906
Posts |
My 2018 never clunks while driving. Only time I've heard it was occasionally shifting into first after having reversed into my parking spot. Previous RWD 6MT have made similar noises so I didn't really think anything of it
__________________
2009 328i xDrive 6MT (Retired and I miss her)
2015 335i xDrive 6MT (Retired and I dont miss her) 2018 M2 6MT (Never retiring) |
Appreciate
0
|
09-08-2020, 01:49 PM | #13 | ||
Private First Class
165
Rep 171
Posts |
Quote:
|
||
Appreciate
0
|
09-08-2020, 01:54 PM | #14 | ||
Private First Class
165
Rep 171
Posts |
Quote:
|
||
Appreciate
1
omasou2088.00 |
09-08-2020, 02:47 PM | #15 | |||
Luxury at the redline :)
9105
Rep 7,563
Posts |
Quote:
The diff is electronic, with a real-time temperature sensor, so if something would to go a-wire, the malfunction light would definitely illuminate. However, its good that you got it documented with a dealer, should something does go bad in the future, which I doubt it will.. . |
|||
Appreciate
3
|
08-12-2021, 04:42 AM | #18 |
New Member
6
Rep 15
Posts |
I had a great drive this afternoon, but I noticed a clunking noise when down shifting towards the end of my 2hr drive. (6 spd Manual) Seems like it comes from the rear diff. And it occurs when I lift off of the clutch after a down shift with some engine braking.
M car drivetrains are designed to be strong and stiff and the diff and gearbox has more backlash (slack in the gears) than a conventional drivetrain. Hence its a bit noisier and clunkier than a "normal" car. |
Appreciate
0
|
08-12-2021, 11:13 AM | #20 |
Lieutenant Colonel
1410
Rep 1,803
Posts |
Some clunks are normal since there is way less bushing insulation between it and the chassis. You will hear some of the noise due to backlash tolerances.
Many people's sensitivity can account for some variation, so it's difficult to separate that from normal and not.
__________________
-2014 328d Wagon, 8HP. Self-tuned, 270hp/430ft-lbs.
-2019 M2 Competition MT, Alpine White. Self-tuned 560hp -2016 Mini Cooper S, MT. Many plans. Others: -E36 328is. 2000 Z3 Roady. 2003 VW Jetta TDI Manual. Estoril Z3M Coupe. |
Appreciate
0
|
08-12-2021, 12:22 PM | #21 |
Just an F Series Owner
24
Rep 68
Posts |
Sounds similar? Scanned it at the dealer with ISTA (3 times visit for the past 6 months) there appear to have no fault code related to the gearbox.
The only fault code is caused by my downpipes. And i am stock with no tune whatsoever. Also posted a thread about this, 1 guy is like "get it checked asap it doesnt sound good" 1 guys is like "drivetrain sounds are normal, shouldnt worry too much" Link to the thread https://www.bimmerpost.com/forums/sh...php?p=27908734 |
Appreciate
0
|
04-24-2024, 10:44 PM | #22 | |
Captain
1045
Rep 605
Posts
Drives: M2C
Join Date: Sep 2013
Location: Seattle
|
Quote:
Sadly all previous videos are no longer working so I can’t compare. Here’s mine: https://youtube.com/shorts/S3Dby5dJs...h2KmXFa2-RI1km I’ve had my car for almost 4 years and > 30k miles and this only began happening yesterday after I took it into the dealer for a rear tire change and alignment. I don’t remember it happening before but at the same time I’m not sure how a tire change could have triggered it especially if it really is related to rear diff…. I’m supposed to leave on a ~5000 mile road trip across the country next Friday 5/3 and ideally this will have stopped by then… As you can see in the video it’s a bit of a small but audible clank that happens under initial load / brisk acceleration. Of course most frequently occurs from a stand-still but as shown in the video it can happen when you’re already moving and you apply sudden load / acceleration. |
|
Appreciate
0
|
Post Reply |
Bookmarks |
|
|