Clunk in the drivetrain

[aussiem3]

Lately I have been hearing a clunk when cruising in high gear, a noise one would associate with an older 10-20 year-old well run in cars. More like some slack in the drivetrain. Has anyone experienced this?
I have seen a couple of threads on diff and mechanical noises. I am not sure whether we're talking about the same thing. My apologies if it's the same.

I don't think it is something bad or detrimental to the performance, it is more in terms of comfort.

[Jasonnator]

6MT or DCT?

[aussiem3]

I should have stated - 6MT

[JCtx]

You need to explain better under what circumstances you hear it. The drivetrain slop is very evident at low rpm due to a jerky throttle. And yes, it's even more jerkier when cold. But I've never heard anything at high speed, although drivetrain slop never disappears, so it's possible you're hearing it if abruptly cutting throttle or accelerating. I honestly don't hear it, but I bet if I turn stereo off, and look for it, I probably would. Explain better what you're experiencing to comment. Take care.

[aussiem3]

It is audible at 60km/h cruising in 5th or 6th gear, and I am not sure whether is exist at higher speed but then wind and road noise might make it impossible to hear.
It is a sound I associate in an old and high mileage car with wear in the driveline which leads to excessive play - my 1986 E28 5er - when you're in a higher gear - 5th - and doing a midget under 60 km/p I constantly hear it. It's annoying and dropping down to a lower gear - 4th cures it.
I haven't tried the same with the E92 and I am sure it would be the same. Yes, with the stereo off you hear it instantaneously. Hope this better explains the condition.
I might drop by at the dealership to have a quick look at things before the warranty runs out in November this year. Can't believe it's three years soon since I got the car.

[M3Bliss]

I wonder if it is the same noise discussed here:

http://www.m3post.com/forums/search....rchid=11950980

To some degree my understanding is that some clunk is normal. I had a first generation CTS V and it suffered from this but it was considered normal and never had any negative effect on performance. BMW had used a different lube in the diffs of cars experiencing this if I am speaking of the same noise; please correct me if I am mistaken.

[JCtx]

Originally Posted by aussiem3

It is audible at 60km/h cruising in 5th or 6th gear

That's not drivetrain slop then. You don't have any slop when drivetrain is under load. You're probably talking about a 'whine', either from the tranny or differential. Most trannies and differentials are going to whine, since they're all churning gears inside, but shouldn't be audible inside the car with stock shifter/insulation. Start by checking fluid levels. The diff is known to clunk due to improper fluid, but that's only when turning sharply.

If you feel it's not normal, I'd first try to meet with other forum members to confirm your suspicion before heading to a dealer. It's hard to even give you an idea what it is over the internet, without any sound clips. Good luck.

[aussiem3]

M3Bliss: I can't find any posts in your link.

The noise is not heard inside the car when the windows are up. Only when down you can hear it coming from under but not sure whether it's the front or the back of the car.
I will replicate it on the way to work and list the exact sequence of events. Thanks for the input so far.