Differential Noise

[OwenT]

Hi All

So the Z4 went in to my Indy for MOT on the weekend; passed no issues.

However, on him driving it back he thinks the rear differential is on its way out Took me for a drive and pointed out the noise symptomatic of it wearing. He's a been a BMW specialist for years and said that over the last 3-4 years they've had several newer 1/3-series with diffs that have gone, whereas it was unheard of in the past.

Anyone have any experience of this on a Z4?

Mine is 4 years / 40k miles old so clearly this is unacceptably early wear. Car is booked into BMW for service in a couple of weeks so asking them to take a look then. Fearing the worst.

Any thoughts lads & ladies?

 

[flybobbie]

To be honest this is my first BMW and i'm not impressed.
I think the overall drive train is not good.
Had old bangers with less, well how can i explain, feeling that there is a load of cogs and gears turning.

Juddering clutch, some noise from the gear box, clunks from the diff.
Heavy non precise steering.
A bit Panzer tank to me.
https://www.youtube.com/watch?v=ROnb5ouBjNc

2:34

 

[OwenT]

Hmmmmm well I wouldn't go that far - the drivetrain is smooth as butter normally, in fact still is apart from the noise that I'm now tunes into...

No ideas anyone??


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[John002]

Not good, mine makes a slight whine after first, second and third gear change whilst accelerating at a normal pace. Is this the noise you're hearing? I thought it normal but now I'm concerned. Can you elaborate on what the mechanic picked up on? Maybe others can put our minds and our warranties at ease.

 

[OwenT]

John - rest your mind, that's not the noise...

You hearing it when cruising slowly (30-40) on a balanced throttle, it's a higher pitched tone than the tyre rumble and exhaust note drowns it out under acceleration. Very hard to describe other than that, it's kind of like 2 smooth pieces of metal rubbing together (it almost is really I think), except the one piece is gradually getting pitted and noisier as a result; causing the noise.

Car booked into BMW now so will update then... Meanwhile any advice welcome!


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[John002]

Panic over, good luck with it Owen...

 

[Stafainn]

I've had a noise coming from my diff for the last couple of years (started about 15,000 miles). Originally I thought it sounded like a rear disc pad rubbing but on further investigation I've been told that its the pinion bearing in my diff that's making the noise. Apparently this is VERY common on BMWs. It seems that the coating on the balls of the bearings wear and that's what causes the "shooshing" noise. Sods law saw that this didn't happen on my car until the warranty was up so I'm forced to either put up with the noise or spend a small fortune replacing the bearing. The good news (if it can be called good news) is that once it happens it shouldn't get much worse and it'll sound really bad before it fails. I'm told that it sounds bad because we almost sit on top of the diff. You can't hear it as bad on one of the saloons. Personally I think that the part is not fit for purpose and should be replaced by BMW at no cost but I'm sure that they'll have a different opinion on that.

 

[Gazzypants]

Hi everyone, so I think I have the exact same issue. Totally as described by John & Owen T. A kind of metal on metal whirring/slight rattle sound, consistent with the momentum of the car, in low gears at normal revs or when coasting in low gears.

Is the diagnosis just to leave it until it goes “kaput”!? Would changing the oil/fluid not make a difference?

 

[B21]

You can leave it but it get messy and awkward…I’d suggest you start looking for a 2nd user diff on eBay and get it sorted..change the oil on the new one!

 

[javis20]

I recently had this issue. 2011 auto 3.0 with 70K miles. Dealer wanted $4000 to replace. I found a very good condition (32k miles) differential on Ebay for $535 shipped. Indy did the swap for around $400. Perfect now. Btw, my diff was starting to leak on one side.

 

[Gazzypants]

Thanks both. Confirmed my suspicions. Will let you know how I get on

 

[flybobbie]

To be honest this is my first BMW and i'm not impressed.
I think the overall drive train is not good.
Had old bangers with less, well how can i explain, feeling that there is a load of cogs and gears turning.

Juddering clutch, some noise from the gear box, clunks from the diff.
Heavy non precise steering.
A bit Panzer tank to me.
https://www.youtube.com/watch?v=ROnb5ouBjNc

2:34

9 years on!!
I have noticed all the clunks and rattles on my morning reversing turn and noisy gearbox have gone.
Over the years changed tyres, shocks, reset camber. One or other cured the problem