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Ask your sales and service advisors for the number to the local Mercedes-Benz dealership.
 

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Discussion Starter #23
Have they put you off the marque completely or just the prospect of keeping this car?
Still love BMWs but if they won't fix this F10 under warranty what hope is there in the future? Probably more a problem with this particular dealership that is owned by BMW of North America.
 

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Still love BMWs but if they won't fix this F10 under warranty what hope is there in the future? Probably more a problem with this particular dealership that is owned by BMW of North America.
Never got the warm & fuzzies from Manhattan, but that was my experience...I'm sure that people think they are the best...
Yours is a very disturbing story because you would like to think that a Factory Store will more than willing to correct this type of issue...
I've left the BMW ranks....kept my F80 for almost 2 years..while it is faster than my E92 and did handle better..it just did not feel right for me...the steering was numb/sterile....the interior styling was nice..and the ride was fine...didn't care for the shifter too much...again just my personal experience with mine...and I have been driving M3' since my first E30 in 1989....
when my new ride arrives at the end of September you should take it for a spin...I'm thinking the spirit of the E39 M5 in this new one!
Best of Luck Ray
 

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Discussion Starter #25
Just for laughs I've attached the latest BMW of Manhattan's invoice for work they did on my DCT clutch problem. It's clear to me that they have dumbed down the DCT software because in their estimation engine braking capability is unimportant to the demographic of people who buy or lease an F10 M5. This behavior is the new "Normal." FWIW they seemed obsessed with trying to put the blame squarely on Dinan. My independent tests with M-Chanics conclusively proved that the Dinantronics Stage 2 was in no way part of this problem.
 

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Crikey.

While it's nice to see that the technician can at least spell and string together a sentence... the level of denial is fantastic. I thought "They all do that, sir" had gone by the wayside. Clearly I was mistaken.

As an aside, there's an awful lot of personal information on those scans. Just sayin'.
 

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Discussion Starter #28
Crikey.

While it's nice to see that the technician can at least spell and string together a sentence... the level of denial is fantastic. I thought "They all do that, sir" had gone by the wayside. Clearly I was mistaken.
I'm convinced BMW deliberately modified the DCT software to lessen the possibility of damage. Didn't they do something like this to the E60's SMG?

It probably happened during an earlier service visit and I didn't catch it right away because you only see it at highway speeds. After two futile service visits to try and get BMW of Manhattan to fix the problem (they declared it 'fixed' on both visits), I took it my Indy George Boutsikos and we saw what was happening. The dual clutches were releasing when they shouldn't, both on manual downshifting and also during steady state highway speeds.

It's totally destroyed the M driving experience for me. Maybe BMWNA believes I should be driving a 7 series. I'd love to be able to identify the original software that came with my F10 - it was perfect.
 

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When the clutches 'release' as you say they do, can you freely rev the engine yourself, as if you'd depressed the clutch pedal on a manual car and hit the gas pedal? You say the revs stay high, but I'm still not 100% sure I get the issue. There is precious little engine braking with these cars anyway so I'd like to understand the actual fault you experience a little better.
 

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Discussion Starter #30
When the clutches 'release' as you say they do, can you freely rev the engine yourself, as if you'd depressed the clutch pedal on a manual car and hit the gas pedal? You say the revs stay high, but I'm still not 100% sure I get the issue. There is precious little engine braking with these cars anyway so I'd like to understand the actual fault you experience a little better.
In answer to your first question, no. The following is a detailed description of what is happening and confirmed by Rheingold BMW diagnostic software during 3 hours of road testing. I should reiterate that this is a new phenomena which started occurring last April.

When manually downshifting at highway speeds (>60 mph) the F10 rev matches and engine braking begins and then inexplicably the clutches disengage. The net result is that the F10 coasts and the revs stay elevated. Application of throttle is required to re-engage clutches. This phenomena will also occur occasionally while cruising at higher rpms. BMW of Manhattan has finally conceded that the F10 hasn't been fixed and will enter the problem in PUMA.
--Ray
 

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So you change down, the revs rise to match the new gearbox speed, and the revs stay high. Surely they would do, unless you actually change the speed of the car? I don't doubt you have an issue here, I'm just being a bit slow at grasping it - apologies.

There's a few things I can't get my head around, and was hoping you could elaborate on: How do you know the clutches have dis-engaged or re-engaged? Isn't the point of a DCT that one of them is always engaged? Does the software you used to analyse this tell you which of the two clutches is being used to transmit power at any moment? And therefore, is it always the same one 'failing'? Also, which gears does this happen in? Again, apologies if I have completely misunderstood the concept of a DCT gearbox. Perhaps someone could enlighten us?

Thanks,
Barney.
 

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Discussion Starter #32
So you change down, the revs rise to match the new gearbox speed, and the revs stay high. Surely they would do, unless you actually change the speed of the car? I don't doubt you have an issue here, I'm just being a bit slow at grasping it - apologies.
After manually down shifting rev matching occurs and initial engine braking begins. After about 1 second engine braking ceases and revs stay elevated. F10 is coasting with clutches disengaged and Valvetronic keeps racing at rev match rpms. Watched the clutch operation do this while using Rheingold BMW diagnostic software.

There's a few things I can't get my head around, and was hoping you could elaborate on: How do you know the clutches have dis-engaged or re-engaged? Isn't the point of a DCT that one of them is always engaged? Does the software you used to analyse this tell you which of the two clutches is being used to transmit power at any moment? And therefore, is it always the same one 'failing'? Also, which gears does this happen in? Again, apologies if I have completely misunderstood the concept of a DCT gearbox. Perhaps someone could enlighten us?

Thanks,
Barney.
Rheingold allows you to monitor what the DCT clutches are doing. I was driving and George Boutsikos was monitoring Rheingold on his lap top. His observation was that both clutches were disengaging during our testing. It would be the equivalent of what happens when stopped at a traffic light or putting the DCT in neutral.
 

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Hey Ray,

It would be interesting to see, therefore, if you let off the throttle at 60 MPH in 7th and time the deceleration to about 40 MPH....and then do the same from 60 MPH again but immediately downshift to 5th and time deceleration to 40 MPH.

Or even just do it in directly in 5th from 60 MPH down to 40 MPH and compare it to doing it in 7th. You seem to suggest that your car is coasting in gear (clutches disengaged) when 'off throttle'.

According to what you have said, all times should be about the same (save for the initial engine braking of about a second or so when you make a downshift) if the clutches disengages when the throttle is released in gear ?
 

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I'd like to understand how these 'wet' clutches work to really understand what's going on here. I read a bit and I'd never realised just how like an automatic gearbox a DCT is. You never get much engine braking with a traditional auto. Combine that with low compression and you're going to struggle to get much at all - as I find on a daily basis. When the software says the clutches are disengaged, exactly what do they mean? It's not as black and white as a dry clutch...... Can the Rheingold guy offer any insight?
 

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Discussion Starter #35
I'd like to understand how these 'wet' clutches work to really understand what's going on here. I read a bit and I'd never realised just how like an automatic gearbox a DCT is. You never get much engine braking with a traditional auto. Combine that with low compression and you're going to struggle to get much at all - as I find on a daily basis. When the software says the clutches are disengaged, exactly what do they mean? It's not as black and white as a dry clutch...... Can the Rheingold guy offer any insight?
When I first leased my F10 the DCT functioned perfectly in all modes including manual downshifts and engine braking. BMW won't admit it but I'm certain this new behavior is the result of their tinkering with the software. It's no longer fun to drive; might as well get a 7 Series. In addition to the engine braking issue, the F10 frequently maintains highway speeds for protracted periods after taking your foot off the accelerator pedal (think cruise control engagement) which is an even more dangerous situation. This is why it's going back to BMW when the lease ends in October. George Boutsikos at M-Chanics can give you more detail on the tests we conducted.
 

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Discussion Starter #36
Mystery Solved?

Beginning in 2014 BMW installed a "sail/cruise" feature on vehicles with automatic transmissions to improve fuel economy. It is part of Eco-Pro mode. When cruising at speeds of 30 mph to 100 mph in this mode, taking your foot off the accelerator disengages the transmission from the engine and the vehicle coasts. This is a known phenomenon on Boards other than the M5.

Found out about this serendipitously while reading an article about the 2016 7 Series where they were extolling the sail/cruise feature. Supposedly this feature can be turned off through the I drive controller. I will explore this on the coming weekend when we'll be going on a drive.

This alleged feature should not be on an M5 IMHO.
 

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Beginning in 2014 BMW installed a "sail/cruise" feature on vehicles with automatic transmissions to improve fuel economy. It is part of Eco-Pro mode. When cruising at speeds of 30 mph to 100 mph in this mode, taking your foot off the accelerator disengages the transmission from the engine and the vehicle coasts. This is a known phenomenon on Boards other than the M5.

Found out about this serendipitously while reading an article about the 2016 7 Series where they were extolling the sail/cruise feature. Supposedly this feature can be turned off through the I drive controller. I will explore this on the coming weekend when we'll be going on a drive.

This alleged feature should not be on an M5 IMHO.
Any (fuel injected) engine will use zero fuel when coasting on a closed throttle, (ie. lifting off whilst in gear in a manual car) and 'some' fuel when coasting on an idling throttle (ie. clutch pushed in on a manual car). The car is also under less control and so is less safe. On top of that, you refer to your revs staying high, which would surely always use more fuel than either scenario I mentioned above. I can't believe BMW would introduce such a feature, but then I have been wrong before....??
 

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Discussion Starter #38
I agree it makes no sense at all. BMW NA screwed the pooch with my Drivelogic. Glad I am returning it to them on 10/18/16. I am through with BMW for the foreseeable future
 
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