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Discussion Starter · #1 ·
I have been noticing what seems to me, a metallic noise, coming from under the car. Only happens when accelerate from a stop of very low speed. It sounds like something loose however the last time I was under the car I didn't see anything loose (noise was present at that time as well). I can replicate the sound everytime without fail and its finally starting to really bug me. This sound is NOT a clunk, or banging sound you would associate with suspension components. Any suggestions?
 

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I have been noticing what seems to me, a metallic noise, coming from under the car. Only happens when accelerate from a stop of very low speed. It sounds like something loose however the last time I was under the car I didn't see anything loose (noise was present at that time as well). I can replicate the sound everytime without fail and its finally starting to really bug me. This sound is NOT a clunk, or banging sound you would associate with suspension components. Any suggestions?
It's kind of like a metallic rattling noise right? Only happens in slow acceleration from a stop like turning in a parking garage, etc and happens for a second or so and disappears when the car starts to move? I think I hear that same sound. At first I thought it's the exhaust rattling or the heat shields. But now, I think it's the clutch engagement since it ONLY happens from a stop - maybe even the SAC...that's my guess...
 

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I've noticed this on my car as well. I was afraid that it was a sign that the clutch is ging bad, but I don't abuse it and it doesn't slip if I start from 3rd gear. Is the "Clutch Engagement" something that can be replaced or is the sound something else??
 

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Its the center driveline bearing on the front of the driveshaft. it wears over time and rings around inside. Very annoying and should be replaced. Getting to the bearing isn't that bad (take driveshaft down), but removing the old old can be a pain as it is sealed in the driveshaft very tightly. Hope this helps.
 

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I've had what sounds like the same thing for months and my indie has been unable to diagnose it. Its more of a 'clink' than a 'clunk' and the noise is the only symptom.

I will suggest the centre driveline bearing to him.
 

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Discussion Starter · #6 · (Edited)
It's kind of like a metallic rattling noise right? Only happens in slow acceleration from a stop like turning in a parking garage, etc and happens for a second or so and disappears when the car starts to move? I think I hear that same sound. At first I thought it's the exhaust rattling or the heat shields. But now, I think it's the clutch engagement since it ONLY happens from a stop - maybe even the SAC...that's my guess...
Sounds like you might have the exact sound I do. I thought the exhaust hanger was loose but everything was tight and couldn't find anything loose under the car. Seems that it makes its sound once or twice when taking off from a stop.

TCM - I checked realoem and couldn't find what I believe you are talking about. Would you care to ellaborate a little more? Is the part in this diagram? Thanks for your help.

 

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Discussion Starter · #7 ·
I forgot to mention, I can also replicate the sound moving slowly in 1st or 2nd while going over slight dips and turning.
 

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I think i'm experience the same noises, more like a clinking sound as you pull away from either stand still or very slow speeds in 1st or 2nd gear. Can hear the sound bouncing off parked cars on narrow roads.
 

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I also get this in reverse gear.........
 

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Its part #1 in that diagram I beleive. The diagram isnt that great though as the bearing has a little lip to it. I knwo this is the problem as I have replaced a couple on two M5s already and my M5 has it too. Its annoying the heck out of me. Getting done soon. The part itself is only about $10 I beleive.
 

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I'd check your exhaust bushings as well. They may be compressed from the passage of time and can contribute to a clunking noise (starts out as a clink) when you hit large (and then progressively smaller) bumps or accelerate hard enough to move the exhaust.

d-
 

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Discussion Starter · #12 · (Edited)
I'd check your exhaust bushings as well. They may be compressed from the passage of time and can contribute to a clunking noise (starts out as a clink) when you hit large (and then progressively smaller) bumps or accelerate hard enough to move the exhaust.

d-
This noise doesn't take much to create and its definitely not a clunking. At first I did check out the hangers but all was well so I can only assume TCM is right about the diagnosis. Thanks again TCM:M5thumbs:......and I hope your right cause dropping the exhaust isn't that fun.

TCM - One last question. Can you visually see damage to the bearing if it is indeed the problem?
 

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Sounds like you might have the exact sound I do. I thought the exhaust hanger was loose but everything was tight and couldn't find anything loose under the car. Seems that it makes its sound once or twice when taking off from a stop.
It's almost like a metallic creaking noise right? The bearings is an interesting suggestion. However, the sound does not map to a typical bearing failure which is more like a constant whine.

This sound only appears for a sec and only when the clutch is just engaging. I don't know anything about the center driveline bearings and its purpose but if it's disengaged at time of clutch pedal depression, then it could most definitely be the cause of the sound. I don't think I hear it if I am slowly creeping along since I don't have the clutch depressed. I thought originally it was the clutch pedal inside but when I am in the garage I can clearly hear it from the outside.
 

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Discussion Starter · #14 · (Edited)
I don't know how to explain it exactly but its like two thin pieces of metal tapping each other and the pitch is kinda high (not clunking). I know mine isn't clutch related because I can replicate the sound while rolling slowly in 1st or 2nd while making a turn and going over a small dip at the same time.

I'll see if I have enough time to make a video of the sound....it'll be kinda hard with a dinan exhaust but I'll try.
 

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SoCal E39:

You will definately see the damage to the bearing once you take down the driveshaft. The whole outer rubber quide is worn and the metal can be cracking. You will be shocked when you pull it out and compare it to the new piece. You may also want ot replace the guibo while you have it down as its right there too. Please let me know how you make out.
 

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Discussion Starter · #16 · (Edited)
Thanks TCM. I have already replaced the guibo about 3-4k miles ago and I'm on a mission of bringing my 107k mile M5 back to fresh condition with new suspension, engine parts, etc. so this is on my list among many others. Would you recommend replacing any other parts besides that $10 part you were talking about?

I'll probably be doing this repair in the next couple weeks so I'll be sure to keep this thread updated with my progress.
 

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Well, if you have some patience you may want to also replace your shifter carrier bushing on the shifting arm that connects to the transmission gear selector. It wears out over time allowing side to side slop in the shifter. A new one really tightens things up, but it is a pita to get in there.
 

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Being a smart *** here but, when I took my handbrake handle off to adjust the tension in I found $20 in $2 coins! To this day, I haven't been able to figure out how that money could get there. Maybe one or two coins, but not 10!
 

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I got the exact same problem with my M3 e46. The noise happens only in slow speeds, or sometimes, during speed bumps. If I accelerate a little more while i'm in a normal speed (like... 40 miles/hour) i hear the sound, also, but it is considerably more discreet at this speed.

The description of the noise is perfect: sounds like i'm dragging an empty soda can under my car...
 

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The description of the noise is perfect: sounds like i'm dragging an empty soda can under my car...
That describes it for my situation perfectly!cherrsagai
 
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