Possible Diff Issues?

gavinm002 · 03-28-2023, 09:10 AM

Hello!
I have a 2012 e91 6spd with an n52. Recently I've been hearing two odd noises while driving, one of which I am thinking could be a diff going out. Anywhere above around 30mph, I start to hear a moderately loud buzzing noise. The pitch of the buzz increases with speed and is at its loudest on the highway.

The other noise happens only around 50-60mph and seems to be correlated to throttle input. The only thing I can compare it to is a locomotive as it sounds like the car is sort of chugging. Power does not seem to be affected when this noise happens, and there is no jolting or odd movement. I really have no idea what this could be and I have not been able to find any other posts about issues like this.

I've tried capturing these noises on video but they really do not come in well at the speeds I hear them since I have roof rails and a ski box.

For reference, I've done virtually all the big engine maintenance items within the last year (water pump, VCG, Oil filter housing gasket, and oil pan gasket). Car just hit 137k miles.

Please let me know if you have any ideas!
Thanks,
-Gavin

ppointer · 03-28-2023, 02:01 PM

Just last weekend sent my e91 to a friend for his kid. At 130k miles it needed a new wheel bearing on the driver's side rear. But that was clearly audible at 20mph and up. It was not a buzzing noise but more of a whine that went up and down based on speed. I think it is rather common for the e9x series to need a rear wheel bearing or two near the 130k mile range. I would have an independent BMW expert take a look and listen.

lookalikehuuh · 03-28-2023, 03:40 PM

Have you evaluated the wheel bearings for the vehicle? I have needed to replace all rear bearings on both of my cars at least 1x.

You could also check the axle shafts to ensure the boots haven't broken and leaked out all the grease.

gavinm002 · 03-29-2023, 10:58 AM

I have not looked at the wheel bearings yet, the only reason being noise did not sound like a wheel bearing to me. My first car was an E53 X5 that had a wheel bearing go out and it sounded much different. I will still take a look just to make sure as it very well could sound different on this car.

I will check on the cv boots too although I did my front axles a couple of years ago so the rears should be the only possible problem.

Thank you all for your suggestions so far!

drymite · 03-30-2023, 12:26 AM

Does it sound like this ?
https://youtube.com/shorts/7_QQmTKz1SM?feature=share

gavinm002 · 03-31-2023, 03:30 PM

Quote:

Originally Posted by drymite

Does it sound like this ?
https://youtube.com/shorts/7_QQmTKz1SM?feature=share

It is somewhat similar to that, but definitely not as loud. I should have also noted that I do not have any codes like the car in that video.

drymite · 03-31-2023, 05:48 PM

Its not that loud on roads its only loud in the shop. Those light are only on because traction control completely off and was getting up to speed to diagnose.
That car has no lights when on the ground..
if its sounds similar its a differential pinion Bearing.somecases its bad and will cause vibrations and rumbling . In this case it only made a whirring sound with no symptoms of crunching or vibrating or dragging i changed the diff oil and the noise decreased alot and the old oil barely had any metal shavings.
Im not a expert on bmw differentials but with my experience with a dodge nitro differential had the same sound . And everyone said its going to fail and it didnt impact any performance and stayed whinning for 6 years . I woould expect BMW diffs being just as strong... if you feel crunching and vibration and a impact on performance then its recommended to change it

gavinm002 · 04-03-2023, 08:47 AM

Quote:

Originally Posted by drymite

Its not that loud on roads its only loud in the shop. Those light are only on because traction control completely off and was getting up to speed to diagnose.
That car has no lights when on the ground..
if its sounds similar its a differential pinion Bearing.somecases its bad and will cause vibrations and rumbling . In this case it only made a whirring sound with no symptoms of crunching or vibrating or dragging i changed the diff oil and the noise decreased alot and the old oil barely had any metal shavings.
Im not a expert on bmw differentials but with my experience with a dodge nitro differential had the same sound . And everyone said its going to fail and it didnt impact any performance and stayed whinning for 6 years . I woould expect BMW diffs being just as strong... if you feel crunching and vibration and a impact on performance then its recommended to change it

I see. There is no crunching/vibration and performance seems normal. I will most likely just change it anyway and see if that does anything. I'll try and get a video of it this weekend if nothing changes since I'll be taking my roof rails and box off and it should be much easier to hear it.

e91Owner · 04-03-2023, 01:06 PM

I’m surprised no one mentioned the guibo yet—I’ve never experienced it myself, but there are plenty of people who have had similar issues to yours and it was the culprit.

eljay · 04-03-2023, 08:18 PM

The humming /chugging like noise around 50mph is likely center driveshaft bearing (or CSB)
I plan to replace mine in the near future as I have that noise too. It is really only audible on the highway at around 50mph.
I have refreshed my entire underside and changed all the fluids and the noise is still there, so I know it's not diff, axles, bearings etc.

03-28-2023, 09:10 AM	#1
gavinm002 New Member 11 Rep 19 Posts Drives: BMW 328i xdrive Sportwagen 6MT Join Date: Jun 2020 Location: Vermont iTrader: (0) Garage List 2012 BMW 328i xDriv ... [10.00]	Possible Diff Issues? Hello! I have a 2012 e91 6spd with an n52. Recently I've been hearing two odd noises while driving, one of which I am thinking could be a diff going out. Anywhere above around 30mph, I start to hear a moderately loud buzzing noise. The pitch of the buzz increases with speed and is at its loudest on the highway. The other noise happens only around 50-60mph and seems to be correlated to throttle input. The only thing I can compare it to is a locomotive as it sounds like the car is sort of chugging. Power does not seem to be affected when this noise happens, and there is no jolting or odd movement. I really have no idea what this could be and I have not been able to find any other posts about issues like this. I've tried capturing these noises on video but they really do not come in well at the speeds I hear them since I have roof rails and a ski box. For reference, I've done virtually all the big engine maintenance items within the last year (water pump, VCG, Oil filter housing gasket, and oil pan gasket). Car just hit 137k miles. Please let me know if you have any ideas! Thanks, -Gavin
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03-28-2023, 02:01 PM	#2
ppointer Major 750 Rep 1,105 Posts Drives: '01 Z3M, '12 335is, '22 540i Join Date: Jul 2013 Location: FLL iTrader: (4) Garage List 2012 BMW 335i [5.25] 2012 BMW 335is [5.00] 2008 Infiniti QX56 [0.00] 1967 Chevrolet Corv ... [10.00] 2001 M Roadster [10.00] 2022 BMW 540i [0.75] 2009 528i [9.50]	Just last weekend sent my e91 to a friend for his kid. At 130k miles it needed a new wheel bearing on the driver's side rear. But that was clearly audible at 20mph and up. It was not a buzzing noise but more of a whine that went up and down based on speed. I think it is rather common for the e9x series to need a rear wheel bearing or two near the 130k mile range. I would have an independent BMW expert take a look and listen.
	Appreciate 1 gavinm00210.50 Quote

03-28-2023, 03:40 PM	#3
lookalikehuuh Major 706 Rep 1,232 Posts Drives: 2006 330i, 2007 335i Join Date: Sep 2014 Location: San Diego, CA iTrader: (0)	Have you evaluated the wheel bearings for the vehicle? I have needed to replace all rear bearings on both of my cars at least 1x. You could also check the axle shafts to ensure the boots haven't broken and leaked out all the grease.
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03-29-2023, 10:58 AM	#4
gavinm002 New Member 11 Rep 19 Posts Drives: BMW 328i xdrive Sportwagen 6MT Join Date: Jun 2020 Location: Vermont iTrader: (0) Garage List 2012 BMW 328i xDriv ... [10.00]	I have not looked at the wheel bearings yet, the only reason being noise did not sound like a wheel bearing to me. My first car was an E53 X5 that had a wheel bearing go out and it sounded much different. I will still take a look just to make sure as it very well could sound different on this car. I will check on the cv boots too although I did my front axles a couple of years ago so the rears should be the only possible problem. Thank you all for your suggestions so far!
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03-30-2023, 12:26 AM	#5
drymite Second Lieutenant 33 Rep 218 Posts Drives: 06 330i/06 323i/09 323i/07 335 Join Date: Oct 2020 Location: toronto iTrader: (0)	Does it sound like this ? https://youtube.com/shorts/7_QQmTKz1SM?feature=share
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03-31-2023, 05:48 PM	#7
drymite Second Lieutenant 33 Rep 218 Posts Drives: 06 330i/06 323i/09 323i/07 335 Join Date: Oct 2020 Location: toronto iTrader: (0)	Its not that loud on roads its only loud in the shop. Those light are only on because traction control completely off and was getting up to speed to diagnose. That car has no lights when on the ground.. if its sounds similar its a differential pinion Bearing.somecases its bad and will cause vibrations and rumbling . In this case it only made a whirring sound with no symptoms of crunching or vibrating or dragging i changed the diff oil and the noise decreased alot and the old oil barely had any metal shavings. Im not a expert on bmw differentials but with my experience with a dodge nitro differential had the same sound . And everyone said its going to fail and it didnt impact any performance and stayed whinning for 6 years . I woould expect BMW diffs being just as strong... if you feel crunching and vibration and a impact on performance then its recommended to change it
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04-03-2023, 01:06 PM	#9
e91Owner e91Owner 425 Rep 1,130 Posts Drives: 2011 e91 & 2010 e60 Join Date: Mar 2018 Location: Out of the Office iTrader: (0)	I’m surprised no one mentioned the guibo yet—I’ve never experienced it myself, but there are plenty of people who have had similar issues to yours and it was the culprit.
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04-03-2023, 08:18 PM	#10
eljay Colonel 1453 Rep 2,143 Posts Drives: ///M + E91 Join Date: Jun 2010 Location: NS iTrader: (1)	The humming /chugging like noise around 50mph is likely center driveshaft bearing (or CSB) I plan to replace mine in the near future as I have that noise too. It is really only audible on the highway at around 50mph. I have refreshed my entire underside and changed all the fluids and the noise is still there, so I know it's not diff, axles, bearings etc.
	Appreciate 0 Quote