Groaning from rear diff area in slow turns

consolidated · 12-15-2008, 11:18 PM

Anyone get an short and intermittent medium pitched groaning/hum sound from the rear end of the car when taking slow but sharp turns, first gear?

Only does it under slight power, experimented with turns in neutral and no sound. Sounds like its coming from the differential.

It's not tires/wheels, doesn't sound like bad wheel bearings in my experience but I'm not sure.

ericld · 12-15-2008, 11:25 PM

yes, you need to take her in and get the service bulletin performed. THey add a higher viscosity diff fluid.

Widely known issue, but it's not hurting your car so walk, don't run, to your dealer

BTW- the sound is diff clutch plates rubbing (did i say that right?)

watrob · 12-15-2008, 11:33 PM

Yeah, take to the service dept they will put a half litre of FMBooster fluid into the diff.

kmac1980 · 12-16-2008, 08:20 AM

there is a LONG post on this already... this noise is normal for a LSD, and the service bulletin addresses customers unhappy with the noise, not that there is actually a mechanical problem. Lots of much more expensive cars w/ LSD exhibit this noise at slow cornering as normal operation....

ericld · 12-16-2008, 08:03 PM

I will add that the service bulletin rectifies the problem 100%.

I had crazy obnoxious groan and it's all gone. Has been gone for months.

achenator · 12-16-2008, 08:15 PM

the m5's and m6's i drove at the m school did the same thing

chris719 · 12-16-2008, 08:31 PM

I had it in my Z4M and it went away after about 3000 miles.

consolidated · 12-16-2008, 08:35 PM

thanks all, thankfully I enjoy going to my dealership they have better coffee than my office

kmac1980 · 12-17-2008, 12:13 PM

i have heard though that TOO much of the additive from the service bulletin to reduce noise also could reduce performance (cause slippage) of the lsd (probably only on the track)

watrob · 12-17-2008, 05:21 PM

Quote:

Originally Posted by kmac1980

i have heard though that TOO much of the additive from the service bulletin to reduce noise also could reduce performance (cause slippage) of the lsd (probably only on the track)

No more than 1/2 a litre is to be added!

12-15-2008, 11:18 PM	#1
consolidated Lieutenant Colonel 207 Rep 1,864 Posts Drives: F80 M3 Join Date: Jun 2007 Location: Texas iTrader: (2) Garage List 2016 Porsche GT4 [0.00] 1999 Porsche Spec B ... [0.00] 2014 Ram 1500 Laram ... [0.00] 2007 Porsche GT3 RS [10.00] 2013 Tesla Model S 85 [0.00]	Groaning from rear diff area in slow turns Anyone get an short and intermittent medium pitched groaning/hum sound from the rear end of the car when taking slow but sharp turns, first gear? Only does it under slight power, experimented with turns in neutral and no sound. Sounds like its coming from the differential. It's not tires/wheels, doesn't sound like bad wheel bearings in my experience but I'm not sure.
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12-15-2008, 11:25 PM	#2
ericld Second Lieutenant 24 Rep 237 Posts Drives: 2008 BMW E92 M3, Alpine White Join Date: May 2008 Location: CO iTrader: (0)	yes, you need to take her in and get the service bulletin performed. THey add a higher viscosity diff fluid. Widely known issue, but it's not hurting your car so walk, don't run, to your dealer BTW- the sound is diff clutch plates rubbing (did i say that right?)
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12-15-2008, 11:33 PM	#3
watrob Lieutenant Colonel 140 Rep 1,597 Posts Drives: MY2022 X5 M-Sport 45e White Join Date: Sep 2008 Location: Brisbane - Australia iTrader: (0) Garage List 2021 Toyota Yaris Z ... [0.00] 2022 BMW X5 G05 e45 [0.00] 2015 Ferrari Cali T [0.00]	Yeah, take to the service dept they will put a half litre of FMBooster fluid into the diff. __________________ MY22 X5 M-Sport 45e White, 22"rims, Red Calipers, Ceramic Pads. Better off saying what it does not have and that's a B&O Audio System, otherwise all option boxes are ticked.
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12-16-2008, 08:20 AM	#4
kmac1980 Major 36 Rep 1,043 Posts Drives: '19 540xi Join Date: Jan 2006 Location: toronto iTrader: (1)	there is a LONG post on this already... this noise is normal for a LSD, and the service bulletin addresses customers unhappy with the noise, not that there is actually a mechanical problem. Lots of much more expensive cars w/ LSD exhibit this noise at slow cornering as normal operation....
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12-16-2008, 08:03 PM	#5
ericld Second Lieutenant 24 Rep 237 Posts Drives: 2008 BMW E92 M3, Alpine White Join Date: May 2008 Location: CO iTrader: (0)	I will add that the service bulletin rectifies the problem 100%. I had crazy obnoxious groan and it's all gone. Has been gone for months.
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12-16-2008, 08:15 PM	#6
achenator Lieutenant 27 Rep 549 Posts Drives: 2017 LBB M2, 2017 R8+ Join Date: Feb 2008 Location: Louisiana iTrader: (0)	the m5's and m6's i drove at the m school did the same thing
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12-16-2008, 08:31 PM	#7
chris719 Major General 7368 Rep 7,323 Posts Drives: '08 M Roadster Join Date: Oct 2007 Location: NJ iTrader: (0)	I had it in my Z4M and it went away after about 3000 miles.
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12-16-2008, 08:35 PM	#8
consolidated Lieutenant Colonel 207 Rep 1,864 Posts Drives: F80 M3 Join Date: Jun 2007 Location: Texas iTrader: (2) Garage List 2016 Porsche GT4 [0.00] 1999 Porsche Spec B ... [0.00] 2014 Ram 1500 Laram ... [0.00] 2007 Porsche GT3 RS [10.00] 2013 Tesla Model S 85 [0.00]	thanks all, thankfully I enjoy going to my dealership they have better coffee than my office
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12-17-2008, 12:13 PM	#9
kmac1980 Major 36 Rep 1,043 Posts Drives: '19 540xi Join Date: Jan 2006 Location: toronto iTrader: (1)	i have heard though that TOO much of the additive from the service bulletin to reduce noise also could reduce performance (cause slippage) of the lsd (probably only on the track)
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