Diff noise in tight turns when cold?

[adc]

For a few weeks now I've been hearing this low rumble/friction noise when tightly turning out of my driveway in the morning. It's sort of a grumble-grumble-grumble from the rear, as if the diff was sticking a little bit, only happens first thing in the morning (everything cold) and only in very tight turning.

Is anybody else getting this? Is this normal for clutch type limited slips, or M diffs in general?

Or could it be something else? Some physical rubbing outside the drivetrain?

[BigHat]

Originally Posted by adc

For a few weeks now I've been hearing this low rumble/friction noise when tightly turning out of my driveway in the morning. It's sort of a grumble-grumble-grumble from the rear, as if the diff was sticking a little bit, only happens first thing in the morning (everything cold) and only in very tight turning.

Is anybody else getting this? Is this normal for clutch type limited slips, or M diffs in general?

Or could it be something else? Some physical rubbing outside the drivetrain?

Without hearing it for myself I answer with caution but I think this probably fine. You ever do a series of tight turns and figure eights when you first got it? Maybe warm up the car and do 20 right turns at steering limit, same to the left and equal figure eights and see what it sounds like the next day.

[adc]

Originally Posted by BigHat

Without hearing it for myself I answer with caution but I think this probably fine. You ever do a series of tight turns and figure eights when you first got it? Maybe warm up the car and do 20 right turns at steering limit, same to the left and equal figure eights and see what it sounds like the next day.

Will do, thanks!

[JCtx]

It's normal, but there's a cure for it. Most of us got the 'cheap' diff oil at the 1.2K-mile service, which is prone to chatter. Mine doesn't do it yet, but read it starts after a few thousand miles. The more expensive diff oil with special additives eliminates that. Do a search for the correct p/n. Some dealers change it out and others don't, but it takes less than 2 qts so it's an inexpensive fix.

[adc]

Originally Posted by elp_jc

It's normal, but there's a cure for it. Most of us got the 'cheap' diff oil at the 1.2K-mile service, which is prone to chatter. Mine doesn't do it yet, but read it starts after a few thousand miles. The more expensive diff oil with special additives eliminates that. Do a search for the correct p/n. Some dealers change it out and others don't, but it takes less than 2 qts so it's an inexpensive fix.

Got it: 83-22-2-282-583

I'll call and complain, see what happens... Actually my oil is due for a change in 3k, maybe I'll wait until then.

[J08M3]

make sure when they change the oil the do the proper break in procedure or you will still hear the noise. it requires 20 tight right hand turns and 20 tight left hand turns. all they do is replace the fluid in the diff with the fluid they used to use in the e46.

[tha_good_life]

I have the same problem. I had a feeling it was not normal but remember hearing it when I first bought the car.

[adc]

Well, I did the 20 tight turns in one direction, followed by 20 tight turns in the other. The noise is still there - so I talked to my SA and they'll take care of it during the next oil change.

[SenorFunkyPants]

Mine does exactly the same but as long as it goes away when hot its probably best to leave well alone. The fix is to change the diff oil to one with extra friction modifiers ie make the diff work less efficiently by allowing the diff clutch plates to slip easier. There is however a school of thought that this is not necessarily a good idea...if nothing else, if it was a good fix with no downside then BMW would simply use the modified oil as the original factory fill for the diff.

[tha_good_life]

I just searched the forum and found this:

This Service Information bulletin supersedes SI B33 01 02 dated March 2008.

SUBJECT
Grinding Noise from the Differential during Slow Cornering

MODEL
E90, E92 and E93 M3 from start of production

SITUATION
A grinding noise may be heard coming from the differential during slow cornering. This noise is best heard during tight cornering situations; for example, while parallel parking, driving in a tight circle, etc.

CAUSE
When the rear wheel speed differential varies during tight cornering, a slip stick effect is created on the lining and steel discs incorporated in the differential locking clutch, causing the grinding noise. This noise typically goes away as the locking clutch discs in the differential are broken in.
The break-in time varies depending on driving habits; for example, tighter cornering (working the locking clutch) means that it takes less time to break in the locking clutch discs.

CORRECTION
If a customer complaint is verified as described above on the E46 M3; E60 M5; E63 and E64 M6; or on the E90, E92 and E93 M3 vehicles, the differential oil should be replaced with a specially formulated differential oil, BMW part number 83 22 2 282 583.
PROCEDURE
1. Drain the differential oil. Refer to the appropriate model repair instruction in TIS:
Main Group 33 / Subgroup 10 / RA 0011259.
2. Refill the differential with special differential oil as shown in the illustration below.
Differential fill capacity = 1.2 liters (1.3 quarts).
3. Road test the vehicle.
With the vehicle at operating temperature, drive in tight circles (20 circles in each direction), allowing the special oil to coat the locking clutch discs.
The grinding noise will decrease when the locking clutch discs are sufficiently coated. Some slight noises may still be heard after driving in tight circles. Advise the customer that it will be necessary to drive the vehicle up to 600 miles before all noises are eliminated.
Note: Vehicles that have had the differential oil converted to this special oil should continue to use this oil whenever a service requiring the differential oil replacement is indicated.

[BobsM3Coupe]

Originally Posted by SenorFunkyPants

Mine does exactly the same but as long as it goes away when hot its probably best to leave well alone. The fix is to change the diff oil to one with extra friction modifiers ie make the diff work less efficiently by allowing the diff clutch plates to slip easier. There is however a school of thought that this is not necessarily a good idea...if nothing else, if it was a good fix with no downside then BMW would simply use the modified oil as the original factory fill for the diff.

BMW doesn't put the good stuff in from the factory because it costs 3 times as much as the cheap stuff. They are doing a wait and see routine of any possible complaints.

[SenorFunkyPants]

Originally Posted by BobsM3Coupe

BMW doesn't put the good stuff in from the factory because it costs 3 times as much as the cheap stuff. They are doing a wait and see routine of any possible complaints.

The modified oil is simply the original factory fill Castrol SAF-XJ diff oil to which BMW chuck in a tube of $2 friction modifiers.
But anyway the OP can do what he likes, I put the alternative side to the story and its up to him...when my SA noted that my car acted the same way when cold and asked if I wanted the modified oil, I declined in no uncertain terms...I'll put up with the odd groan when my car is cold, to be more confident that the diff will do its proper job when hot.

[ploo]

I get the same noise, but I've always thought it was normal differential noise - I have almost 7000 miles now. I'm not 100% sure but I think I get it when the car is fully warmed up, as well. Should I bring it in to have the diff oil replaced ASAP? Will find an empty parking lot later today to verify if the noise occurs both cold and warmed.

[bobbyd1961]

bring it to dealer. they can change the fluid and solve the problem easily

[ploo]

Originally Posted by bobbyd1961

bring it to dealer. they can change the fluid and solve the problem easily

Thanks...is it urgent? I work 80 hours a week and it can be a mess trying to get the car in and being able to pick it up and return the loaner during normal business hours. An alternative is to take every corner with throttle-induced oversteer to minimize the delta in rear wheel speeds

[adc]

Originally Posted by SenorFunkyPants

The modified oil is simply the original factory fill Castrol SAF-XJ diff oil to which BMW chuck in a tube of $2 friction modifiers.
But anyway the OP can do what he likes, I put the alternative side to the story and its up to him...when my SA noted that my car acted the same way when cold and asked if I wanted the modified oil, I declined in no uncertain terms...I'll put up with the odd groan when my car is cold, to be more confident that the diff will do its proper job when hot.

I appreciate the info you posted, it certainly gave me some food for thought.

I'm not sure that a BMW service bulletin would result in the diff being less effective. The fact that some cars have this noise and others don't smacks of manufacturing tolerances. Certainly, the ideal way is for the diff not to make these noises - I doubt the slip/stick effect was designed into it from the very start.

The other aspect is that I may end up keeping this car for a long time - I imagine that the slip-stick effect only adds to the diff wear.

I could be mistaken of course. I'll talk to my SA who is a true enthusiast and has had several M3's in the past - I'll probably listen to his advice, whatever that may be.

[adc]

Originally Posted by ploo

Thanks...is it urgent? I work 80 hours a week and it can be a mess trying to get the car in and being able to pick it up and return the loaner during normal business hours. An alternative is to take every corner with throttle-induced oversteer to minimize the delta in rear wheel speeds

Not urgent - my SA was very specific about that. When is your next oil change due?