differential whine

wanna6 · 10-17-2016, 03:33 PM

I purchased a 2014 CPO M6GC CP w/ 22k miles.

Upon driving home from dealer I noticed a loud howl when laying off the throttle
on highway coasting around 75-90MPH. I took it to dealer and they diagnosed it
as a bad differential an ordered a replacement.

1 week later as i was driving home with the new differential I noticed the whine
was still there, only not as bad as before it would really shriek.

I called SA and he said it should get better when they put the break in diff oil at
1.2k miles but that I should expect to hear some kind of noise from the diff.

I had break in done a week ago and have since put around 500 miles on the car
yet it still has a subtle howling sound when cruising on the highway around the
same speeds.

I wanted to ask you guys is it normal to have any kind of differential whine when
coasting on the highway around 75-90MPH (only when laying off the throttle or
on cruise control, as the noise goes away if I give it alittle gas)

M5 London · 10-17-2016, 04:53 PM

Not normal at all !

Is the car modified in any way at all ?

wanna6 · 10-17-2016, 08:44 PM

no mods

TrevorM3 · 10-18-2016, 08:29 PM

this differential thing i really getting out of control. m3 guys, m5 and m6's, my car during production.. jesus christ

wanna6 · 10-19-2016, 12:04 PM

what makes it frustrating is I still have the whine after a brand new differential was installed... going to have to go to a 2nd dealer to see if they can rectify the issue

wanna6 · 10-21-2016, 11:06 AM

From what I gather BMW makes an SAF-XJ+FM fluid that has a friction modifier(FM) additive
part # 83222282583

Going to ask my SA to run this by the shop foreman and see if it may help my situation...
This whine is horribly annoying when cruising on the highway. Amazing that a new diff
still whines as well

10-17-2016, 03:33 PM	#1
wanna6 Private 11 Rep 51 Posts Drives: . Join Date: Apr 2015 Location: United States iTrader: (0)	differential whine I purchased a 2014 CPO M6GC CP w/ 22k miles. Upon driving home from dealer I noticed a loud howl when laying off the throttle on highway coasting around 75-90MPH. I took it to dealer and they diagnosed it as a bad differential an ordered a replacement. 1 week later as i was driving home with the new differential I noticed the whine was still there, only not as bad as before it would really shriek. I called SA and he said it should get better when they put the break in diff oil at 1.2k miles but that I should expect to hear some kind of noise from the diff. I had break in done a week ago and have since put around 500 miles on the car yet it still has a subtle howling sound when cruising on the highway around the same speeds. I wanted to ask you guys is it normal to have any kind of differential whine when coasting on the highway around 75-90MPH (only when laying off the throttle or on cruise control, as the noise goes away if I give it alittle gas)
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10-17-2016, 04:53 PM	#2
M5 London Second Lieutenant 331 Rep 231 Posts Drives: F90 M5 LCI - Aventurine Red Join Date: Oct 2014 Location: South Kensington, London iTrader: (0)	Not normal at all ! Is the car modified in any way at all ? __________________ F90 M5 LCI - Aventurine Red/Smoked White-E39 M5 - Modified ESS Supercharger Kit -E34 M5 1995 - Arctic Silver / Black Leather- E30 M3 1987 - Diamond Black Metallic / Black Leather-996 Turbo - Lapis Blue/Savannah-VW Rallye Golf
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10-17-2016, 08:44 PM	#3
wanna6 Private 11 Rep 51 Posts Drives: . Join Date: Apr 2015 Location: United States iTrader: (0)	no mods
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10-18-2016, 08:29 PM	#4
TrevorM3 Banned 3322 Rep 8,083 Posts Drives: 6.3 AMG Join Date: Apr 2013 Location: Florida iTrader: (0)	this differential thing i really getting out of control. m3 guys, m5 and m6's, my car during production.. jesus christ
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10-19-2016, 12:04 PM	#5
wanna6 Private 11 Rep 51 Posts Drives: . Join Date: Apr 2015 Location: United States iTrader: (0)	what makes it frustrating is I still have the whine after a brand new differential was installed... going to have to go to a 2nd dealer to see if they can rectify the issue
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10-21-2016, 11:06 AM	#6
wanna6 Private 11 Rep 51 Posts Drives: . Join Date: Apr 2015 Location: United States iTrader: (0)	From what I gather BMW makes an SAF-XJ+FM fluid that has a friction modifier(FM) additive part # 83222282583 Going to ask my SA to run this by the shop foreman and see if it may help my situation... This whine is horribly annoying when cruising on the highway. Amazing that a new diff still whines as well
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