BMW head technician's input on differential noise tolerance range...

eNCore · 10-24-2011, 01:14 AM

I have a 2011 DCT. I've been getting a light knocking/clunking noise from the car when it comes to a stop (stop sign/stop light) and at low speed (0-10 mph). I did a lot of research on the forum but all I can find is differential noise when turning and clutch noise from 6MT. The noise is quite small so I can't really record it. I asked and went on a test drive with a BMW head tech and he told me it's from the differential and it's normal. I asked if they can fix it by adding the differential oil and he told me it's only for noise when making turns. He also told me there is a sound tolerance range for the differential to be considered normal.

The noise is pretty light and can only be heard when the windows are up and without music, but it is quite annoying when you pay attention to it.

My question is...am I the only one getting this noise, or many are getting it too, or it's there many just don't notice it? Or I just have the bad luck of getting a differential that just barely made it within the tolerance range of being considered normal?

Radiation Joe · 10-24-2011, 03:55 AM

It sounds like you're talking about the gear rattle at a stop. If you push in the clutch, does it go away? If it does go away with the clutch pushed in, it's the gear rattle which is normal.

karussell · 10-24-2011, 04:49 AM

this is exactly why auto companies like bmw will continue to put more sound deadening material in the cabin and then enhance the engine noise with fake noise from sound system. the mechanical differential in the M3 is a technical masterpiece. I would say its better than whats used in Porsche GT cars.

don't obsess over the little stuff. enjoy the car. if you want dead quiet bmw product, go to a Roller.

InterJon · 10-24-2011, 09:11 AM

"DCT" people! What you hear is normal gear "chatter" from the transmission. This is completely normal on the DCT. Also took me a while to get used to it.

Mike van D · 10-24-2011, 02:43 PM

It's normal...no worries.

10-24-2011, 01:14 AM	#1
eNCore ///M 5light 244 Rep 439 Posts Drives: 13 MCB ///M5 Join Date: May 2008 Location: Los Angeles, 626 iTrader: (1)	BMW head technician's input on differential noise tolerance range... I have a 2011 DCT. I've been getting a light knocking/clunking noise from the car when it comes to a stop (stop sign/stop light) and at low speed (0-10 mph). I did a lot of research on the forum but all I can find is differential noise when turning and clutch noise from 6MT. The noise is quite small so I can't really record it. I asked and went on a test drive with a BMW head tech and he told me it's from the differential and it's normal. I asked if they can fix it by adding the differential oil and he told me it's only for noise when making turns. He also told me there is a sound tolerance range for the differential to be considered normal. The noise is pretty light and can only be heard when the windows are up and without music, but it is quite annoying when you pay attention to it. My question is...am I the only one getting this noise, or many are getting it too, or it's there many just don't notice it? Or I just have the bad luck of getting a differential that just barely made it within the tolerance range of being considered normal? __________________ 13 MCB ///M5 11 - 12 MW E92 ///M3 ZCP 08 - 11 E90 335i Last edited by eNCore; 10-24-2011 at 01:28 AM..
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10-24-2011, 03:55 AM	#2
Radiation Joe Veni Vidi Vici 89 Rep 2,750 Posts Drives: '11 JB/BBe-6sp-e90 Join Date: Jul 2008 Location: Macungie PA iTrader: (0) Garage List 2011 e90 M3-Sold [8.50] 2003 RS6 - Sold [0.00] 2009 e90 M3 - Gone [0.00] 2003 M3 SOLD [0.00] old 2002 [10.00]	It sounds like you're talking about the gear rattle at a stop. If you push in the clutch, does it go away? If it does go away with the clutch pushed in, it's the gear rattle which is normal. __________________ Dinan compliment of stuff plus PF rotors and RG63s. Enough for now. Why, yes. I am an abrasive bastard.
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10-24-2011, 04:49 AM	#3
karussell Lieutenant Colonel 353 Rep 1,749 Posts Drives: 4 wheels Join Date: Sep 2009 Location: NorCal iTrader: (1)	this is exactly why auto companies like bmw will continue to put more sound deadening material in the cabin and then enhance the engine noise with fake noise from sound system. the mechanical differential in the M3 is a technical masterpiece. I would say its better than whats used in Porsche GT cars. don't obsess over the little stuff. enjoy the car. if you want dead quiet bmw product, go to a Roller. __________________ "It gave you amazing satisfaction, but anyone who says he loved it is either a liar or he wasn't going fast enough." - Jackie Stewart on racing at the Nurburgring
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10-24-2011, 09:11 AM	#4
InterJon Second Lieutenant 10 Rep 201 Posts Drives: 2011 E92 M3 ZCP Join Date: Aug 2011 Location: Alabama iTrader: (0)	"DCT" people! What you hear is normal gear "chatter" from the transmission. This is completely normal on the DCT. Also took me a while to get used to it.
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10-24-2011, 02:43 PM	#5
Mike van D Major 18 Rep 1,112 Posts Drives: SG X6 35i; MW e92 M3 Join Date: Jan 2011 Location: Germany iTrader: (0)	It's normal...no worries. __________________ ...just enjoying life.
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