clunk sound

Jm5900 · 07-02-2018, 09:53 AM

sup everyone I was hoping to get some help

I'm in the process of buying a used BMW M3 from a local bmw dealership and when I took it on a test drive I could hear a clunk sound coming from the back of the vehicle every time I took a turn... not sure what it is (bushings, control arms, rear diff) but I told the dealer that needed to be fixed first before I would buy the car.

Today I get a call from the dealer advising me that the car was inspected and all it needs is for a "rear clutch differential adjustment" to be done.

Does this sound normal? I've never heard of a differential adjustment before.

I appreciate all the feedback thank you!

BOOF-M3 · 07-02-2018, 02:02 PM

deansbimmer sorry to bother you Dean, hoping you may have an idea for a local buddy.

deansbimmer · 07-02-2018, 07:10 PM

Oh, no biggie, just the everyday rear clutch differential adjustment? Is that like the headlight fluid you need to top up at each oil change? SMH.

If there is a clunk back there on turns then its a broken bushing or part not an adjustment.

PACarGuy · 07-02-2018, 08:10 PM

The M3 has a limited slip variable locking differential with a viscous coupling, which can fail (and cause clunking). It can be rebuilt, but I didn't think there was an "adjustment" that can be made to it to fix that issue...maybe they mean a rebuild?

330ciprem · 07-02-2018, 08:28 PM

Maybe it can be the infamous cow-bell clunk?

Jm5900 · 07-02-2018, 08:53 PM

So I requested the work order from service showing what was done on this “adjustment” the sales rep was talking about and ends up being they Replaced the diff fluid per bmw bulletin that’s what the notes say. Im hoping it’s the cow bell clunk which after reading that thread is very similar to what I was experiencing on the test drive.

Jm5900 · 07-02-2018, 08:55 PM

Quote:

Originally Posted by PACarGuy

The M3 has a limited slip variable locking differential with a viscous coupling, which can fail (and cause clunking). It can be rebuilt, but I didn't think there was an "adjustment" that can be made to it to fix that issue...maybe they mean a rebuild?

What can a rebuild cost at a independent shop any idea? I imagine a rebuild would be worse case scenario?

SS e93 · 07-02-2018, 10:24 PM

The cowbell clunk isn't associated with turning from what I can recall. I have it intermittently at low speeds like stopping or starting at a light.

Jm5900 · 07-02-2018, 11:16 PM

Quote:

Originally Posted by SS e93

The cowbell clunk isn't associated with turning from what I can recall. I have it intermittently at low speeds like stopping or starting at a light.

yea I remember hearing it mostly on right turns not sure it was doing it on normal stop and go.

Jm5900 · 07-02-2018, 11:32 PM

question the car was involved in a rear end collision where per the carfax it states minor damage. could the rear diff have been affected by a "minor accident".

deansbimmer · 07-03-2018, 07:11 AM

I wouldn’t describe noisy diff clutches on tight turns as a clunk. It’s more of a repeatable grind than a clunk. Entirely possible that is what you’re experiencing.

Jm5900 · 07-03-2018, 07:25 AM

Quote:

Originally Posted by deansbimmer

I wouldn’t describe noisy diff clutches on tight turns as a clunk. It’s more of a repeatable grind than a clunk. Entirely possible that is what you’re experiencing.

Thats the first thing I came across on the forums the grinding noise but it doesn’t sound grinding at all. It’s definitely more one clunk type noise.

And the turns not tight I was hearing it on 120-130 degree turns coming out of shopping centers onto the far left lane.

JRV · 07-03-2018, 08:05 AM

I had this problem and I think the dealer changed the diff oil and that was that. It happened on slow right turns.

Jm5900 · 07-03-2018, 11:55 AM

Quote:

Originally Posted by JRV

I had this problem and I think the dealer changed the diff oil and that was that. It happened on slow right turns.

Dealer changed the oil already and they are telling me the car is now good to go. Just nervous I buy the car and a month from now I need a new diff. How long has it been running without issue?

JRV · 07-03-2018, 12:08 PM

Quote:

Originally Posted by Jm5900

Quote:

Originally Posted by JRV

I had this problem and I think the dealer changed the diff oil and that was that. It happened on slow right turns.

Dealer changed the oil already and they are telling me the car is now good to go. Just nervous I buy the car and a month from now I need a new diff. How long has it been running without issue?

Years at least 5-6. It happened maybe 1 year or so of ownership and since then it's been fine.

CjM3 · 07-03-2018, 01:10 PM

Test drive it one more time after they said they fixed it?

PACarGuy · 07-03-2018, 02:05 PM

Quote:

Originally Posted by Jm5900

What can a rebuild cost at a independent shop any idea? I imagine a rebuild would be worse case scenario?

Not sure if most shops would take that on but I imagine it's somewhere in the $1-2K range.

BOOF-M3 · 07-03-2018, 02:11 PM

Quote:

Originally Posted by CjM3

Test drive it one more time after they said they fixed it?

Yea, use launch control a couple of times or at least once to make sure it holds up.

deansbimmer · 07-03-2018, 03:04 PM

These diffs rarely blow up. The clutches might start slipping but most drivers would never know anything was wrong. Most shops won’t rebuild the oem viscous diff but would upgrade it to something else like an OS Giken at a cost of a few thousand. Replacement used diffs run a grand or so. None of those should be huge issues to someone considering owning an M3. If I were you I’d be more concerned over finding out when or if the rod bearings were replaced.

Jm5900 · 07-03-2018, 08:54 PM

Quote:

Originally Posted by CjM3

Test drive it one more time after they said they fixed it?

yup definitely test driving it one more time before taking possession.

BOOF-M3 · 07-03-2018, 09:01 PM

Quote:

Originally Posted by Jm5900

Quote:

Originally Posted by CjM3

Test drive it one more time after they said they fixed it?

yup definitely test driving it one more time before taking possession.

Check it from 60 to 75mph for shaking/pulling to either side. Bent rims or messing an alignment is quite common.

Jm5900 · 07-03-2018, 09:02 PM

Quote:

Originally Posted by deansbimmer

These diffs rarely blow up. The clutches might start slipping but most drivers would never know anything was wrong. Most shops won’t rebuild the oem viscous diff but would upgrade it to something else like an OS Giken at a cost of a few thousand. Replacement used diffs run a grand or so. None of those should be huge issues to someone considering owning an M3. If I were you I’d be more concerned over finding out when or if the rod bearings were replaced.

I'm pretty sure the bearing have not been changed as this was a one owner, older gentleman driven car. The car looks super clean, id bet almost anything this car has had zero mods done. I'm more worried about the 1k miles put on the car since it got to the dealer.

As soon as I get the car ill have the oil changed and sent over to get checked. I was hoping I could hold off maybe a 2-3 months before doing the bearings but the results of the oil report will dictate that.

07-02-2018, 09:53 AM	#1
Jm5900 Enlisted Member 9 Rep 39 Posts Drives: 335i Join Date: Jan 2009 Location: at home iTrader: (0)	clunk sound sup everyone I was hoping to get some help I'm in the process of buying a used BMW M3 from a local bmw dealership and when I took it on a test drive I could hear a clunk sound coming from the back of the vehicle every time I took a turn... not sure what it is (bushings, control arms, rear diff) but I told the dealer that needed to be fixed first before I would buy the car. Today I get a call from the dealer advising me that the car was inspected and all it needs is for a "rear clutch differential adjustment" to be done. Does this sound normal? I've never heard of a differential adjustment before. I appreciate all the feedback thank you! Last edited by Jm5900; 07-02-2018 at 12:04 PM..
	Appreciate 0 Tweet Quote

07-02-2018, 02:02 PM	#2
BOOF-M3 Brigadier General 4452 Rep 4,014 Posts Drives: 2011 M3 Join Date: Nov 2014 Location: South Pasadena Florida iTrader: (1)	deansbimmer sorry to bother you Dean, hoping you may have an idea for a local buddy.
	Appreciate 1 Jm59008.50 Quote

07-02-2018, 07:10 PM	#3
deansbimmer BimmerPost Supporting Vendor 3752 Rep 2,907 Posts Drives: 2011 E93 M3 Join Date: Nov 2014 Location: DFW, Texas iTrader: (17) Garage List 1988 BMW M3 [0.00] 2013 BMW M3 [0.00] 2011 X5M [0.00] 2011 BMW M3 [0.00]	Oh, no biggie, just the everyday rear clutch differential adjustment? Is that like the headlight fluid you need to top up at each oil change? SMH. If there is a clunk back there on turns then its a broken bushing or part not an adjustment.
	Appreciate 3 BOOF-M34451.50 Jm59008.50 timothy2001850.00 Quote

07-02-2018, 08:10 PM	#4
PACarGuy Captain 684 Rep 973 Posts Drives: 2012 E92 M3 DCT ZCP Join Date: Nov 2015 Location: Philly burbs, PA iTrader: (1) Garage List 2012 E92 M3 [8.33] 2019 G01 X3 (wife's) [0.00]	The M3 has a limited slip variable locking differential with a viscous coupling, which can fail (and cause clunking). It can be rebuilt, but I didn't think there was an "adjustment" that can be made to it to fix that issue...maybe they mean a rebuild? __________________ 2012 E92 M3 \| ZCP \| DCT \| Space Grey Metallic \| Black Novillo \| BE/ARP \| MPE V2 \| AA green filter \|BMW CF Rear Spoiler, RW Carbon Diffuser, CF Front Splitters \| DTEC 160W Angel Eyes
	Appreciate 1 Jm59008.50 Quote

07-02-2018, 08:28 PM	#5
330ciprem Lieutenant 229 Rep 415 Posts Drives: 12 E92 M3, 06 E46 330ci, 6spds Join Date: Jan 2018 Location: Indianapolis iTrader: (0)	Maybe it can be the infamous cow-bell clunk?
	Appreciate 1 Jm59008.50 Quote

07-02-2018, 08:53 PM	#6
Jm5900 Enlisted Member 9 Rep 39 Posts Drives: 335i Join Date: Jan 2009 Location: at home iTrader: (0)	So I requested the work order from service showing what was done on this “adjustment” the sales rep was talking about and ends up being they Replaced the diff fluid per bmw bulletin that’s what the notes say. Im hoping it’s the cow bell clunk which after reading that thread is very similar to what I was experiencing on the test drive.
	Appreciate 1 PACarGuy683.50 Quote

07-02-2018, 10:24 PM	#8
SS e93 Captain 27 Rep 850 Posts Drives: e93 M3 Join Date: Sep 2009 Location: new york iTrader: (2)	The cowbell clunk isn't associated with turning from what I can recall. I have it intermittently at low speeds like stopping or starting at a light.
	Appreciate 1 Jm59008.50 Quote

07-02-2018, 11:32 PM	#10
Jm5900 Enlisted Member 9 Rep 39 Posts Drives: 335i Join Date: Jan 2009 Location: at home iTrader: (0)	question the car was involved in a rear end collision where per the carfax it states minor damage. could the rear diff have been affected by a "minor accident".
	Appreciate 1 BOOF-M34451.50 Quote

07-03-2018, 07:11 AM	#11
deansbimmer BimmerPost Supporting Vendor 3752 Rep 2,907 Posts Drives: 2011 E93 M3 Join Date: Nov 2014 Location: DFW, Texas iTrader: (17) Garage List 1988 BMW M3 [0.00] 2013 BMW M3 [0.00] 2011 X5M [0.00] 2011 BMW M3 [0.00]	I wouldn’t describe noisy diff clutches on tight turns as a clunk. It’s more of a repeatable grind than a clunk. Entirely possible that is what you’re experiencing.
	Appreciate 1 Jm59008.50 Quote

07-03-2018, 08:05 AM	#13
JRV Captain 119 Rep 922 Posts Drives: 2011.75 AWE90M3 Join Date: Aug 2008 Location: CT iTrader: (1)	I had this problem and I think the dealer changed the diff oil and that was that. It happened on slow right turns. __________________ '11 Black/Black GLK350 (Wife) '19 Black RAM 1500 Big Horn Night Package '11 Loaded AW Fox Red/Black/Black Carbon Leather ZCP E90 M3 (Halloween Delivery)
	Appreciate 1 Jm59008.50 Quote

07-03-2018, 01:10 PM	#16
CjM3 Private First Class 42 Rep 167 Posts Drives: E92 M3 Join Date: Mar 2015 Location: Bothell iTrader: (0)	Test drive it one more time after they said they fixed it?
	Appreciate 1 Jm59008.50 Quote

07-03-2018, 03:04 PM	#19
deansbimmer BimmerPost Supporting Vendor 3752 Rep 2,907 Posts Drives: 2011 E93 M3 Join Date: Nov 2014 Location: DFW, Texas iTrader: (17) Garage List 1988 BMW M3 [0.00] 2013 BMW M3 [0.00] 2011 X5M [0.00] 2011 BMW M3 [0.00]	These diffs rarely blow up. The clutches might start slipping but most drivers would never know anything was wrong. Most shops won’t rebuild the oem viscous diff but would upgrade it to something else like an OS Giken at a cost of a few thousand. Replacement used diffs run a grand or so. None of those should be huge issues to someone considering owning an M3. If I were you I’d be more concerned over finding out when or if the rod bearings were replaced.
	Appreciate 4 BayE301341.00 PACarGuy683.50 BOOF-M34451.50 Jm59008.50 Quote