DCT Revs and Speed question

[nseah]

This is my first time with a DCT, my previous cars have been manuals. In a manual, when you engage the clutch in gear and push the gas the revs build as the speed builds. In my DCT focus, when it shifts into 3rd and 4th gear and the clutch engages (i'm continueously giving it gas) the revs seem to bounce a bit up and down at first as the speed increases. After maybe 1 or 2 seconds the clutch locks and the revs build as it should.

In a manual car this would be clutch slipping, but with a DCT i'm not sure if this is some sort of feature that makes the gear changes more smooth (i.e. slowly matching the revs with the speed). The ride is still smooth, but my concern is that doing this constantly would lead to faster clutch wearing no?

has anyone else noticed this in their car? should this be something I should be concerned about?

I also noticed that this only happens when im driving the car at a casual pace. If i'm really pushing the pedal the shifts are noticeable and the revs build as soon as the clutch locks (no bouncing around).

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[dan50]

Mine does the same thing. Ford mentions the concept of "microslip" in the DCT which I interpret as allowing the clutch to slip slightly make the experience a bit smoother. In some conditions, mine will even exhibit this behavior if gas is given suddenly when cruising, but not enough so as to cause a downshift.

Let's hope this is normal. Maybe the Ford rep could comment. Cory?

[FordCustomerService]

Originally Posted by dan50

Mine does the same thing. Ford mentions the concept of "microslip" in the DCT which I interpret as allowing the clutch to slip slightly make the experience a bit smoother. In some conditions, mine will even exhibit this behavior if gas is given suddenly when cruising, but not enough so as to cause a downshift.

Let's hope this is normal. Maybe the Ford rep could comment. Cory?

Hi dan50,

Cory is working on a new project so I'll be stepping in to assist.

Since I'm not a mechanic, I'm not in the best position to answer technical questions. Your local dealership's service manager is a great resource for determining whether or not your vehicle's behavior is normal.

Crystal

[dan50]

Originally Posted by FordCustomerService

Hi dan50,

Cory is working on a new project so I'll be stepping in to assist.

Since I'm not a mechanic, I'm not in the best position to answer technical questions. Your local dealership's service manager is a great resource for determining whether or not your vehicle's behavior is normal.

Crystal

Crystal, you are such a kidder! Ford service departments will declare pretty much any DCT behavior "normal" if that's the convenient answer.

Welcome back.

[nseah]

Hmm ok, well its good to hear others experiencing this and it's not just me. I figured it was some kind of feature to make the shifting smoother and more automatic-like. My thoughts are doing the slipping constantly over time will lead to faster wear.

[mp223]

I too have noticed the same behavior, "microslip." Details are sparse, but I would assume it's clutch slippage to make smoother shifts. Certainly that will wear the clutch down faster. I'm sure Ford has designed the transmission in such a way to last through the warranty period, but after that, who knows. Clutches are wear parts after all.

Also do not expect Cory or any Ford rep to comment. Cory isn't here to answer questions, just to escalate customer issues.

[mark3inline]

Since this type of trans/engine management has been used in F1 for what the last 15 years. With drive by wire throttle, the ecu controls everything, air, fuel, ignition, clutch, and shifting. I undestand this isn't a million dollar control system but, Europe has been using this in the Focus two years before released here, didn't they learn anything from that ?

[Kabigon]

Originally Posted by mark3inline

Since this type of trans/engine management has been used in F1 for what the last 15 years.

F1 cars use a dual clutch transmission similar in operation to that of the Focus (and not a single clutch sequential transmission)?
Are you sure?

Originally Posted by mark3inline

With drive by wire throttle, the ecu controls everything, air, fuel, ignition, clutch, and shifting.

That's not how it works in the Focus. There is a separate PCM and TCM.

Originally Posted by mark3inline

I undestand this isn't a million dollar control system but, Europe has been using this in the Focus two years before released here, didn't they learn anything from that ?

The first (and only other) application of the Focus DCT was in the Fiesta.

[raptor1956]

Originally Posted by mark3inline

Since this type of trans/engine management has been used in F1 for what the last 15 years. With drive by wire throttle, the ecu controls everything, air, fuel, ignition, clutch, and shifting. I undestand this isn't a million dollar control system but, Europe has been using this in the Focus two years before released here, didn't they learn anything from that ?

F1 cars do NOT use DCT or dual clutches at all. The gears are very, no make that VERY slim and would not last very long in street use but then they don't have to last very long and they make them as light as possible to reduce weight, and more importantly, moment of inertia. The trick to F1 gear boxes is the shifting mechanism that can complete the shift in much less than 25msec, some say as low as 10msec. There is no micro slipping between gears...


Brian

[Dysan911]

Im glad you brought this up. I've been meaning to do the same. I notice this behavior with highway on-ramps. I will get a rate of acceleration I'm comfortable with and hold that.. The Speed and RPM's seem to be climbing at a synchronized rate and then on 3rd gear or 4th.. Maybe both. Thats when the RPM side just hovers around 3k RPMish but the Speed is still rising so I assume if the clutch was slipping like it would in a traditional manual tranny my speed would be dropping off.

Like you, this behavior concerns me of clutches slipping and burning up. If I let up on the gas it seems to do this less and will just shift into 5th/6th.

I've never smelled burnt clutch so it must be by design. (at least that's what convinces me).

FWIW, My clutches were completely replaced a few months back due to a TSB involving leaking seals. Prior to getting the clutches replaced. My shifts were all over the place, never could find the right gear and made a horrible noise at some RPM's. After the new clutches, it's like a completely brand new car. No shifting problems except for just this strange slipping sensation.

I definitely hope it's supposed to do that and that I'm not looking at replacing clutches at 36k miles.

I firmly believe though that the DCT tranny will never see 100k miles without some major repairs. If it turns out the average life of the DCT transmission exceeds 100k. I'll be mighty impressed.