Clunking Noise from rear Diff area

[Big Zed]

I hope someone can help or advise where to go.

I have a 2004 Z4. I have a clunking noise thats getting gradually worse, The noise appears to be coming from around the rear diff area.

The noise ALWAYs happens when I pull off or when I reverse and sometimes while braking

I have changed the rear diff bushes.... didn't work and cost a fortune.

The BMW dealers are useless and overpaid.

I have tried a diff specialist and they dont think it is the diff.

I have taken the car to various garages and no one will commit to a solution.

Someone has suggested the Prop Donut which is £68 which I dont mind but paying... if it cures it.

Please Help Someone???

Thanks

[christurbo]

It sounds like some kind of bushing failure. If you had an E46 then I would suggest the subframe bushes.

[torino]

Think this is a common 'ish' problem, mine does it too!

Sounds like a bit of slack when taking up drive? it doesn't feel like there's any slack though?

If you try and turn the prop with the rear jacked up can you re-create the noise?

Think i remember reading it's nothing to worry about and the only way to get rid of the noise is by replacing the diff?

Drive it till it breaks?

Sorry, just realised that wasn't the most usful of replys Hopefully someone else might have a better awnser!

[Big Zed]

Thanks Chaps,

Just found a mechanic who apparantly knows all about this problem.

Its going in on Tuesday after I pick it up from bodyshop (somebody went into side of me)

I'll let you know the outcome and cost....

It will hopefully be the end of my frustrating 3 months quest to solve this problem.

Thanks again

[Siftah]

Thanks Chaps,

Just found a mechanic who apparantly knows all about this problem.

Its going in on Tuesday after I pick it up from bodyshop (somebody went into side of me)

I'll let you know the outcome and cost....

It will hopefully be the end of my frustrating 3 months quest to solve this problem.

Thanks again

Will be interested to hear as I'm pretty sure I have a similar noise - sort of a metallic clunk. Usually happens in 1st/2nd gear (or at least, It's not loud enough to be heard at higher speeds), sometimes happens when going over speed bumps or low speed braking at junctions etc.

Hard to pin down, but doesn't feel serious

[daveparkinson]

did you find the cause of that diff noise

[yg54sg]

I have a noise like this and like yours it has gotten worse over last year or so, to make the noise I put the car in gear let the clutch out and you get a short metallic tap, it will even do it if you apply the handbrake, both in forward and reverse gears. Sounds like something is loose somewhere. I have an inspection pit and quite a good ear (found my ex girlfriends squeek on her 106 when 2 garages couldnt! Just needed a bit of grease on a barcket underneath where metal to metal was rubbing ever so slightly on a cover) I plan to fit the polyurthane bushes to the front soon so will do it then. It certainly is annoying in stop start traffic with the roof off! tap tap tap....

[Russ59]

Mine does it too. It passed MOT last week so wouldnt think its a bush problem hence it would have been picked up by MOT tester (watched him test the car).

Be happy to know just what it is though.

[Big Zed]

Eventually.....

The clunk which was the Diff, then the gear box, then Prop Donut (totally split) and then the Diff again noise was actually an apparrant common problem on the 3 series in which our fine cars are built on!!!

The answer is cheap and simple....Were the prop enters the diff requires a special lube adding as whatever was in there before has turned to powder...

I can refer anyone to the garage I used, they were actually helpfull and interested in my problem and could describe it better than me

They are a new BMW independant garage in the Midlands.

Thanks for everyones advice and help.

[doofus4000]

Eventually.....

The clunk which was the Diff, then the gear box, then Prop Donut (totally split) and then the Diff again noise was actually an apparrant common problem on the 3 series in which our fine cars are built on!!!

The answer is cheap and simple....Were the prop enters the diff requires a special lube adding as whatever was in there before has turned to powder...

I can refer anyone to the garage I used, they were actually helpfull and interested in my problem and could describe it better than me

They are a new BMW independant garage in the Midlands.

Thanks for everyones advice and help.

Can I ask do you know what sort of 'special lube' they used to cure this and how did they go about it? I think I have the same problem as you. Many thanks.

[doofus4000]

Eventually.....

The clunk which was the Diff, then the gear box, then Prop Donut (totally split) and then the Diff again noise was actually an apparrant common problem on the 3 series in which our fine cars are built on!!!

The answer is cheap and simple....Were the prop enters the diff requires a special lube adding as whatever was in there before has turned to powder...

I can refer anyone to the garage I used, they were actually helpfull and interested in my problem and could describe it better than me

They are a new BMW independant garage in the Midlands.

Thanks for everyones advice and help.

Can I ask do you know what sort of 'special lube' they used to cure this and how did they go about it? I think I have the same problem as you. Many thanks.

[doofus4000]

Would this be the special lube or is it just a sealant?

http://www.realoem.com/bmw/showparts.do ... g=33&fg=10 item no.7

[doofus4000]

or is this it?

http://www.bmwinformation.co.uk/dg/bmwa ... gi-pdf.pdf

Item no.1?

Sounds like the right stuff. If so how did you all apply it? I wouldnt be attempting this but my mechanic friend would and I would like to give him a heads up on what others have done if this is the cure.

[Shooter]

Now that's interesting...
I was going for the long, hard and expensive way to circumvent (fisrt time i ever use this word in a real sentence, hop it's the good one ) the all-too annoying "clunk" noise, meaning full silent-blocks change (from front suspension rear control arm ones to diff supports, including the "flector"). But if it comes down to only add a bit of lube costing only 10 or so bucks, i'm in !

[doofus4000]

Well I dont know shooter, I was thinking the same as yourself. All I know for definite is that I have this clunk at the rear - have done a load of research and didnt find anything on the z4-forum. Thought I give the e46 forums ago as the cars are similar in that respect and learnt of all these parts that wear on the e46 like diff joints, u joint, centre bearings etc. So I got a mechanic friend to put her up on the ramp - he checked everything in the drivetrain that he could apart from inside the actual diff. Everything was solid - she is a 07 coupe with only 24K on the clock!

Then last night I spent ages searching again and got back to the z4-forum and found this thread - jez how did I miss it the first time!!! So the guys above have used this as a fix so I am wanting to know details!? Indeed it sounds like a real cheap fix but sounds too good to be true lol