DCT rattle/buzz

[s2000jan]

Anyone - with DCT - experienced the following?

When in N or P, the DCT has a 'rattle', very mechanical not too loud but very noticeable .... at idle rpm

When upping the rpm's the noise disappears (above 1000 rpm)

Maybe it is because I'm still in the break-in period ? (have done about 500km)

Anyone a clue ?

[teagueAMX]

There was another report of some sound coming from the DCT, but I don't think it was the actual DCT. Sound like that is typically something loose, like a exhaust pipe.

BTW - the the DCT shouldn't be making any kind of rattle or vibration sounds, new or otherwise. If you had it on a hoists and stood under the car and heard a sound like that coming from the DCT, you've got a problem. Dealer would likely have to pull the DCT out and replace it - I don't think the dealers are repairing them.

But, I don't think that's your problem.

[Vintage]

no rattles or noises with our DCT

[s2000jan]

Originally Posted by VintageBMW

no rattles or noises with our DCT

mmm, weird ...

the sound is gone the moment I put it into D, so must be linked to the transmission

[Wraith.]

keep us updated on this...

[s2000jan]

Originally Posted by jannisa

I get this noise from day one. No problem ever mentioned. Does anyone else have it?
http://www.youtube.com/watch?v=q8qaBcQAy5M

You are talking about the noise the DCT-shifter itself makes when going from D to N to P and vice versa .... that's normal, but it is not that noise that I'm having.

If I find some time, I'll try to you-tube the sound

[Wraith.]

Originally Posted by s2000jan

You are talking about the noise the DCT-shifter itself makes when going from D to N to P and vice versa .... that's normal, but it is not that noise that I'm having.

If I find some time, I'll try to you-tube the sound

.. and please capture a sound bite of the exhaust on your iS while your at it.

[T89]

Originally Posted by jannisa

I get this noise from day one. No problem ever mentioned. Does anyone else have it?
http://www.youtube.com/watch?v=q8qaBcQAy5M

Yep this is normal. It's the shifter itself making the noise, not the transmission.


T

[teagueAMX]

Originally Posted by s2000jan

Anyone - with DCT - experienced the following?

When in N or P, the DCT has a 'rattle', very mechanical not too loud but very noticeable .... at idle rpm

When upping the rpm's the noise disappears (above 1000 rpm)

Maybe it is because I'm still in the break-in period ? (have done about 500km)

Anyone a clue ?

Originally Posted by s2000jan

You are talking about the noise the DCT-shifter itself makes when going from D to N to P and vice versa .... that's normal, but it is not that noise that I'm having.

If I find some time, I'll try to you-tube the sound

Apart from what some have mentioned such as the shifter vibrating or rattling, or something really unusual such as loose bolt, exhaust pipe, etc., one thing that is known with the n54 engine is the turbo wastegates rattle.

Disclaimer: Not trying to be scary and am not saying you have that problem, and can’t say if the sound pattern fits that issue but I mention it for information purposes only!

There’s a huge thread on it E90Post forum. BMW had trouble with turbo lag with the n54 which was related to software control of the turbocharger wastegates. The turbocharger wastegates are controlled by the ECU software. When the engine idles, the ECU need to dump turbo boost so it opens the wastegate. Apparently the software was a little sensitive.

It’s been a month or so since I kept up with it, but BMW was modifying the software that controls wastegates. The last I heard BMW pretty much had it fixed, but given they tinkered with the 35iS software to increase boast and horsepower. . . FWIW

http://www.e90post.com/forums/showthread.php?t=147781

http://www.e90post.com/forums/showth...ight=wastegate

[s2000jan]

Thanks teagueAMX !

It could well be that ... did not yet listen to the clip you posted (don't want my co-workers to wake up )
Will try to go through the complete post (>100 pages!) and see whether it is that

How do I know what software version I'm on ?

Concerning the 'lag' ... I do have that (I think) ...

Will need to inform my dealer probably ...

Is the wastegate rattling problem a major problem ? Or just an annoying sound ? Or will it fail in the end ?

[teagueAMX]

If in fact that is the problem, not saying it is, but if you haven't noticed a drop in your performance such as a short delay when you step on the gas, the rattle is not harmful and just an annoying sound.

There's a way to tell what version of the software you have, but your car is a new model, right, so I don't think any of the version numbers they talk about over there would apply to you, maybe they would - just not sure.

Based on reading that thread, it seems that BMW updates the ECU software quite often. In your case, if that is the problem, more than likely it's something BMW has to tweak rather than some of the other issues the e90 group has dealt with.

[s2000jan]

Originally Posted by teagueAMX

If in fact that is the problem, not saying it is, but if you haven't noticed a drop in your performance such as a short delay when you step on the gas, the rattle is not harmful and just an annoying sound.

There's a way to tell what version of the software you have, but your car is a new model, right, so I don't think any of the version numbers they talk about over there would apply to you, maybe they would - just not sure.

Based on reading that thread, it seems that BMW updates the ECU software quite often. In your case, if that is the problem, more than likely it's something BMW has to tweak rather than some of the other issues the e90 group has dealt with.

Thanks ! If the sound is just 'annoying' then it is not urgent (I suppose)

And yes, my car is brandnew, so I would think the software is the latest one (like the iDrive soft which is dated March 2010)

Loss of performance is too early to say as I'm in the break-in period, but it does accelerate very good (below 4000rpm that is)

[teagueAMX]

Right, it's not urgent.

All turbos have a least a tiny bit of lag, but as you drive your car some more you'll get to know it better and a feel for it if it's got any significant lag or not.

Wouldn't worry about it's not life or death.

[s2000jan]

Originally Posted by teagueAMX

Right, it's not urgent.

All turbos have a least a tiny bit of lag, but as you drive your car some more you'll get to know it better and a feel for it if it's got any significant lag or not.

Wouldn't worry about it's not life or death.

true, but my previous car had the same N54 engine but was a manual and with the DCT it reacts completely different ... so, still learning (the DCT)

[Memphis1]

Have you tried resetting the tranny??

I did at around 3500 and it did feel smoother and more responsive

[s2000jan]

Originally Posted by memphis2012

Have you tried resetting the tranny??

I did at around 3500 and it did feel smoother and more responsive

Ah yes, that's something that I've read somewhere that this is possible ... you got the link somewhere to that procedure ? (too lazy to search )

[Memphis1]

http://www.bimmerfest.com/forums/sho...d.php?t=411543

[s2000jan]

Originally Posted by memphis2012

http://www.bimmerfest.com/forums/sho...d.php?t=411543

That's the one ! I knew I've read it before !

Thanks !

[alan64]

Originally Posted by T89

Yep this is normal. It's the shifter itself making the noise, not the transmission.


T

they all do that.

[s2000jan]

added to this topic: it also 'rattles' when putting it in 'D' without driving ....

[teagueAMX]

Originally Posted by s2000jan

added to this topic: it also 'rattles' when putting it in 'D' without driving ....

Did you watch the tube vids or record the sounds yours make?

[s2000jan]

Originally Posted by teagueAMX

Did you watch the tube vids or record the sounds yours make?

Not yet ... and next week some holiday, so will take another week to do so

I watched the vids but the sound does not resemble mine