M4 DCT Auto start/stop "Clunk"

[James_m4]

As per the title.

I've noticed that when, say in traffic, and Auto stop/start is functioning the gearbox (by the gear selector) seems to make a dull clunk when the engine stops and again when it starts.

I thought this maybe just the car taking itself out of 1st and into N? Now im starting to think maybe not?

Does anyone else notice this noise?

Thanks

[warrenm14]

I have noticed this... It's very irritating and I don't recall a similar sound on my other car (Audi) with Start/Stop.

Glad it's not just me!

[JustChris]

Not heard this really no. What settings have you been in when it happens?

[James_m4]

Any setting. Doesn't matter. As long as the stop/start function is active then it happens.

[James_m4]

To round this one off. My car is currently with the dealers having is 1,200mile service.

I raised several "items" and so far this is where we are at;

Q1. Clunk from gear box on auto stop/start.
A1. Normal on F80/82 models. This is the sound of an actuator disengaging the box from D/S1 to a position not dissimilar to neutral. But not neutral.

Q2. Condensation build up in both headlights. Enough to form large water droplets on the lenses.
A2. A software parameter test will be undertaken. There is a certain level of condensation accepted this is due to the latest Xenon/LED headlights being ventilated form the rear due to heat. A test can be performed and if the computer confirms loss of visibility outside of a certain parameter the affected headlights will be replaced with a new unit(s)

Q3. M drive "sport" display dials on screen was showing KW instead of HP.
A3. This unit of measurement can be changed as required under vehicle settings >measurements/units

Hopefully that may assist some people

[JustChris]

I noticed the clunk today, nothing too major but good to know the answer above, thanks for this.

[warrenm14]

I'm wondering if I'll turn off the ASS. What do you gents think? I didn't buy an M4 to be concerned with fuel economy

[James_m4]

Originally Posted by warrenm14

I'm wondering if I'll turn off the ASS. What do you gents think? I didn't buy an M4 to be concerned with fuel economy

I have already coded mine out so that when the car starts its automatically off by default!

Happy days!

[singh21]

Originally Posted by Suzuka

I have already coded mine out so that when the car starts its automatically off by default!

Happy days!

Did you code this yourself?

[James_m4]

Originally Posted by singh21

Did you code this yourself?

Yes. I did all my coding myself;

http://f80.bimmerpost.com/forums/sho....php?t=1086996

[gavinsan]

Confirmed clunk on my car also.

Headlights have condensation and will be inspected by dealer soon

[StephPT]

Hi,

I have the exact "problem"
It's not very good to hear that KNOCK every time START & STOP kicks in.

We can say that this is actually "Normal" ?!??!

Thank you

[PA11L JJ]

Mine is always in Sport+ so never have the ASS activated.

[JOHNBMWM5]

Originally Posted by James_m4

As per the title.

I've noticed that when, say in traffic, and Auto stop/start is functioning the gearbox (by the gear selector) seems to make a dull clunk when the engine stops and again when it starts.

I thought this maybe just the car taking itself out of 1st and into N? Now im starting to think maybe not?

Does anyone else notice this noise?

Thanks

I had this in the LCI M5 and the M6 GC CP, but not in this LCI M3, BUT it's normal and nothing to worry about.

[Dieselind]

Hey Guys,

Did this clunking issue ever get sorted? I just noticed it in my car and only just picked it up on Tuesday!

thanks

[cavin.mo]

I noticed that too!!!! Thats why i never use the start/stop

[Wills2]

I don't notice a clunk in mine but that doesn't mean it's not there, one thing that my DCT does occasionally in slow crawling traffic is hold 3rd for too long at very low speeds so the car starts to judder just like it would on a manual if the gear is too high and you don't engage the clutch whilst slowing down.

It also shunts into 1st when it's in a huff!

[pbw]

Have it in mine too. Will mention it when I take it in for its ris in a couple of hundred miles time.

[gatsojon]

Perfectly normal as explained earlier in the post. 'They all do that sir...'

[Wills2]

Listened for it today, it's just a little click I had to turn the radio down to hear it.

[Dieselind]

Thing is, on my car its louder than the music coming from my hk speakers which is worrying so its going back to the dealdership tomorrow for a check up...

[TLA2319]

Hi there - I have the same issue and I was highly sceptical when the dealer said 'they all do that' as I do not recall it happening on the test drive (perhaps the ASS was off). I do find it annoying as it can be heard over the music and you can feel it against your leg - if anyone has had it 'fixed' that would be good to hear.

I think I expect more from BMW with an M car.