Strange Clunk.

[Stee01]

Hi all, trying to diagnose this strange clunk under my 2010 X1. It's the 23D XDrive, 6-spd auto. Had it 4 years trouble-free but recently had new front & back brake rotors & pads fitted as the rotors were worn below specs at 150k km.

Symptoms of the clunk: ONLY happens when car has warmed up after about 10 minutes driving. Only happens while crawling in 1st or 2nd gear on a smooth surface, eg: my work's carpark. Disappears as soon as I turn the wheel, left or right. No issues accelerating hard, or accelerating in a tight circle, so probably not a CV joint, I'm thinking. Clunk was also there before the new brakes were fitted.

Been reading a few threads & it seems that too much difference in tread depth between front & back might be a contributing factor. Our back tyres were worn out so were recently replaced with new tyres. Fronts are only half-worn. Clunk was there before the tyre change but seems a little worse now.

I've had an '08 X3 XDrive for 5 years & not had this issue. Recently traded the X3 on a 2012 X5 & likewise it's fine too.

Any ideas?

[X5Sport]

Tyre tread depth would be my first check. XDrive cars are sensitive to tyres and BMW state in their technical instructions, no more than 2mm variance between any tyre. This usually means changing them as a complete set. It sounds as if you have that issue so need to replace the other pair. Ignoring it can result in an expensive transfer box repair/replacement being needed.

Have you had a fluid change done at all? My X6 started showing odd signs on very smooth car park surfaces even though the tyres are both BMW Approved (have a ‘’ on the sidewall) and changed as sets. It was a slight jerkiness at very low speed. I had all the fluids front to back replaced and the problem went away. BMW insist on the fluids being ‘lifetime’ (3 years according to them!) whereas ZF who make the transmission say change every 8 years or 50,000 miles.

[Stee01]

Tyre tread depth would be my first check. XDrive cars are sensitive to tyres and BMW state in their technical instructions, no more than 2mm variance between any tyre. This usually means charging them as a complete set. It sounds as if you have that issue so need to replace the other pair. Ignoring it can result in an expensive transfer box repair/replacement being needed.

Have you had a fluid change done at all? My X6 started showing odd signs on very smooth car park surfaces even though the tyres are both BMW Approved (have a ‘’ on the sidewall) and changed as sets. It was a slight jerkiness at very low speed. I had all the fluids front to back replaced and the problem went away. BMW insist on the fluids being ‘lifetime’ (3 years according to them!) whereas ZF who make the transmission say change every 8 years or 50,000 miles.

Thanks. I'll measure that in the morning. The car was just serviced at the same time as the brakes were done, but I don't think that the Trans or Transfer were touched. I'll find the invoice & check. The other thing I can do, is try another set of matched wheels (17" x 8") & tyres that I had on my X3, but kept. They're all the same age & wear so that should tell me something, assuming that they fit.

[Stee01]

Ok, mystery hopefully solved & cured. We had to wait until this week for our local Mechanic to open up after Xmas. My Wife took him for a drive, then he drove it & agreed that it was probably driveline. As we have 2 new tyres on the back he suggested as a first step replacing our half-worn front tyres.

There's something of a tyre shortage here in Australia, especially low-profile jobs, but my Wife managed to find 2 for the front & pretty much just like that, the clunk is gone.

I drove it to work today - a 30km drive - then did my usual wind up 6 levels in the work carpark. Smooth, grippy concrete, lots of tight turns, all 1st & 2nd gear work. No clunks & even the transmission was smoother-changing.

The only problem is of course, that it has "staggered tyres" which can't be rotated & the front obviously wears at a different rate to the back. We'll see how we go with it.

[X5Sport]

Most BMWs have the same setup - as do a number of other European Brands (Merc, Porsche, Audi, Jaguar are a few I know of), and those are the ones most likely to have issues. Glad you’ve got this little challenge sorted and before it did any damage.

[Stee01]

Most BMWs have the same setup - as do a number of other European Brands (Merc, Porsche, Audi, Jaguar are a few I know of), and those are the ones most likely to have issues. Glad you’ve got this little challenge sorted and before it did any damage.

The X-Drives, yes. I'm just cranky that this one did it. My old '08 X3 didn't & we had it for 5 years it had 200k+ km up. The X1 is only on 150k km. We traded my X3 on a 2012 X5 recently & it's as smooth as silk so far. I'm keeping a careful eye on it though as we had to put back tyres on it when we bought it but are still waiting for the matching fronts to land - that shortage I mentioned. The fronts are about 70% worn.

I joked with my Daughter that the driveline in her Kia Sportage would last longer than the X1's. Hers is AWD "On Demand" (Ie: wheelspin) but does also have a 4WD-Lock button, for use on LOOSE surfaces only.