DCT noise. What is normal?

[Lambobimmer]

I am posting this here because the Z4 community is somewhat small and I wanted to get more responses about my question.

So I've had my 2009 Z4 35i for about 2 months now and I am learning what is normal and what is not. Before I bought the car the warranty information indicated that the DCT was leaking and fixed at 33,xxx. My car currently has 37,XXX miles. I am not sure what exactly they fixed, only that they fixed a leaky DCT. After I bought the car I felt like it was still leaking and my dealer replaced the gasket on the mechatronics unit. It appears that this has fixed the leak but I am not sure what is normal noise for the DCT tranny.

It sounds very loud to me, almost like a roaring noise. It is difficult for me to determine if the noise that I am hearing is the transmission or the awful Kuhmo Ecsta Spt tires that are currently on it. I am coming from a 135i
6MT that had very little drivetrain noise so I am concerned that something else might be wrong with the DCT.

I would like to hear from other DCT owners about what normal is for this transmission.

I have no complaint about how it shifts. It seems to shift great and fast.

Mods are:
HFP FMIC
KW V3
AR DP's
Milltek Exhaust

[RnmEvo9]

Can you take a video? I have been in several 335is with the DCT tranny and never once have heard any roaring noise. All I heard was engine noise and exhaust.

[panoz7]

I've never noticed any noises from the DCT at all.

It's a bit of a drive, but if you find yourself in the triangle and want to compare, you're welcome to a ride in my car.

[Lambobimmer]

Here are a few vids. I believe that it is tire noise that is making the roaring noise but I am not sure.

http://www.youtube.com/watch?v=6L425LoSnEY

http://www.youtube.com/watch?v=SFylcJSjdcc

http://www.youtube.com/watch?v=g-EBqRPi3BM

[alexmtl_135i]

Not sure I hear anything suspect, but it's hard to tell from a video

[vantagesc]

My DCT is completely quiet in normal operation though in parking structures you can hear the next gear being preselected. More of a changing forks type sound.

There is no gear whine as far as I can tell.

[Mr Kleen]

I really couldn't tell from your video clips what you were hearing, but my DCT doesn't make much noise at all. Are you sure you aren't being paranoid after having the issue with the leak?

[Lambobimmer]

Originally Posted by Mr Kleen

I really couldn't tell from your video clips what you were hearing, but my DCT doesn't make much noise at all. Are you sure you aren't being paranoid after having the issue with the leak?

You might be right about being paranoid. My friend and BMW tech believes that all of the noise coming from my car is tire noise. I might just get rid of the Kuhmo's and replace them with MPSP.

[Dackelone]

^^I was just gonna say tires can make some horrendous bearing type noises when they are worn/old. Buy some quality tires and recheck for the noise. Maybe you have some winter tires you can throw on to check if the noise changes>?

[Ginger_Extract]

My mother's 135i vert w/ DCT trans is as silent as a comparable torque convertor auto or manual transmission. If anything seems suspect, and the car is still under warranty, just take it to the dealership. Why screw with it when you can ge it sorted for free under warranty.

[tuco44]

I am on my second DCT equipped car, and neither of them has had a noisy DCT. Totally quiet.

[Mr Kleen]

Originally Posted by lamboworld

You might be right about being paranoid. My friend and BMW tech believes that all of the noise coming from my car is tire noise. I might just get rid of the Kuhmo's and replace them with MPSP.

It can happen to the best of us. Any time I work on my car I'm super sensitive about noise. "You hear that? Was that noise always there?"

I've had great luck with Kuhmo tires. Check that they're balanced and properly inflated. If you still don't like them, maybe someone has a different set that you can test drive?