HELP - Rear Clunk Noise

[Advantage]

Hey, having a difficult time identifying the source of my problem and could use some help. I am hearing a "clunk or thud noise" from the rear of the car that happens sporadically and only occurs when the car shifts its weight (front to back or left- to-right or right-to-left).

The clunk noise happens - again only occasionally - when moving forward from a dead stop or when doing a moderate turn through a roundabout for instance.

I've had my M5's shocks and springs replaced awhile back under the SIB that was issued. That was more of a harsh feel and noise when going over bumps. This was entirely different from this.

The service technician inspected the car and saw some metal shavings near the differential and replaced the bushings. Although this seemed to help the problem it still happens from time-to-time. It's quite annoying as it's very audible.

Anyone else have something like this? By the way, my car is slightly modified pushing close to 650 whp. Thoughts?

[Advantage]

Bueller? Bueller? Anyone have any suggestions for me?

Thanks for your help! Happy Friday!

[allmotor_2000]

Possibly your diff mount is giving out...

[Advantage]

Originally Posted by allmotor_2000

Possibly your diff mount is giving out...

Thanks for the feedback! I suspect that what might be going on. I will report back after another attempt to resolve it. Have a great weekend!

And looking forward to hearing more about your crazy M5. Would love to see you offer a "built package" for the M5.

[WickedBMW]

If the noise is coming from either left or right rear, it could be your knuckles.

[AKG M3]

I think I might be experiencing something similar. After a drive, when I come home to park the car, I stop, put it in reverse, front wheels turned a bit and if I hit the throttle a bit harder to get the car going back in motion I hear a kinda "snap" metal sound under the car around the rear...doesn't happen all the time though. Seems I can replicate the sound mostly when parking, reversing specifically and when I hit the throttle faster. Snaps once and then no more.

[Advantage]

Originally Posted by AKG M3

I think I might be experiencing something similar. After a drive, when I come home to park the car, I stop, put it in reverse, front wheels turned a bit and if I hit the throttle a bit harder to get the car going back in motion I hear a kinda "snap" metal sound under the car around the rear...doesn't happen all the time though. Seems I can replicate the sound mostly when parking, reversing specifically and when I hit the throttle faster. Snaps once and then no more.

That sounds very similar to what I am experiencing although I have not been able to replicate the issue as you've described. I will try later today.

Yes, your description of a metal "snapping" sound is more accurate. It's almost like there is tension that builds up and then releases (like snapping your fingers) from time to time especially with sudden weight changes.

BTW, I had the diff mount / bushings replaced in the rear and, although it seemed to help, it hasn't resolved the issue 100%.

[AKG M3]

^ Exactly, sounds like we have the same issue and good point to mention it happens when there is a weight change. Just hope its not the DCT

[UnfoundLegend]

http://f10.m5post.com/forums/showthread.php?t=843819

SIB is attached. Let me know if this fixes your problem!

[Advantage]

Originally Posted by UnfoundLegend

http://f10.m5post.com/forums/showthread.php?t=843819

SIB is attached. Let me know if this fixes your problem!

Thank you for sending. However, I had this fixed earlier last year. The current issue feels and sounds different. I'll try and get a video.

[Advantage]

Originally Posted by AKG M3

^ Exactly, sounds like we have the same issue and good point to mention it happens when there is a weight change. Just hope its not the DCT

Are you stock or modified?

[AKG M3]

All stock.

[Advantage]

Originally Posted by AKG M3

All stock.

I tried to replicate your issue by going into reverse slowly and aggressively several different times and was not able to get that metal snapping noise.

[TLK]

Sometimes things with ball joints (like sway bar end-links or control arms) make snapping sounds when they are broken or worn out.

[WickedBMW]

From full stop turn your steering wheel start either left or right for 360 turn than step on a gas pedal (moderate speed). Perform this action in both directions with someone observing rear wheel for a skip while you listen for a clanking noise inside. If both issues confirm; that’s your knuckle problem.

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Originally Posted by WickedBMW

From full stop turn your steering wheel either left or right for 360 turn than step on a gas pedal (moderate speed). Perform this action with someone observing rear wheel for a skip while you listen for a clanking noise inside. If both issues confirm; that’s your knuckle problem.

Thanks for the reply. Okay, I will do that test and report back.

[Advantage]

Originally Posted by TLK

Sometimes things with ball joints (like sway bar end-links or control arms) make snapping sounds when they are broken or worn out.

Thanks for the reply. Next time I bring it in I will have them look at them.

[Advantage]

Originally Posted by WickedBMW

From full stop turn your steering wheel start either left or right for 360 turn than step on a gas pedal (moderate speed). Perform this action in both directions with someone observing rear wheel for a skip while you listen for a clanking noise inside. If both issues confirm; that’s your knuckle problem.

Okay, tried your test several different times both left and right. Was not able to replicate the sound and appeared normal. I think the knuckles are fine.

Thanks again.

[Phahadx]

same issue happening to me please let me know if you fixed it.

[Phahadx]

im having the issue from 0-30 i guess moving the car straight first, second gear from suspension but i dont know whats the part thats damaged it happened yesterday and when i go above 30 it goes away. turning right or left no sound just once moving the car straight.

[Phahadx]

same sound but only straight and i think its from the right front wheel or left front im feeling it in drivers seat however my friend in passengers seat says its so clear.

[Advantage]

Originally Posted by Phahadx

same sound but only straight and i think its from the right front wheel or left front im feeling it in drivers seat however my friend in passengers seat says its so clear.

That sounds different than my issue. I am sure someone on this forumwill be able to diagnose it based on your video. You may want to post a separate thread.