Fellow DCT owners - quick favour

[Helmsman]

Hi fellow DCT owners,

been having the friggin heat code coming and going for years now. Fluid, filters, adaptation reset etc, no result.
Typically turns up after short runs like 8 miles very calm/low rpm from office, even before the engine is at full temp. Goes away after some careful driving.

Favour I'd like to ask:
Could you stick your hand under the bumber and feel whether your DCT fluid heat exchanger is hot already after shorter runs?

Mine is but I have no clue whether it should already after such short driving. If not, it is probably the sensor doing its job, but I so far tend to believe the sensor is playing tricks on me.

Many thanks in advance!

Nik

[Redd]

I'll check for you when I get the car back from vanos cap install. But if the DCT cooler is warm it means oil is going thru and it should be cooling the oil.

I've never ever seen a dct temp warning even when engine oil temps were at the 130+ degC range so definitely something abnormal with yours. I would do a dct adaptations reset and also change the DCT temp sensor first.

[jp1984]

I will check this for ya tomorrow too.

[amrazM]

Originally Posted by Redd

I'll check for you when I get the car back from vanos cap install. But if the DCT cooler is warm it means oil is going thru and it should be cooling the oil.

I've never ever seen a dct temp warning even when engine oil temps were at the 130+ degC range so definitely something abnormal with yours. I would do a dct adaptations reset and also change the DCT temp sensor first.

That sensor is part of the gearbox, it’s not serviceable.

My heat exchanger for the DCT was warm to the touch after backing out of my driveway and driving for 10 minutes. The dct uses coolant from the heads which passes through a heat exchanger mounted on the unit.

Op if you really want to explore this issue you should consider logging your dct temps. It shouldn’t be too far off from the coolant temps when the car starts. My last few dct services when the weather was in the 60s F the dct temp usually hits 90F in about 2 minutes which is when the thermostat opens.

[Helmsman]

Originally Posted by Redd

I'll check for you when I get the car back from vanos cap install. But if the DCT cooler is warm it means oil is going thru and it should be cooling the oil.

I've never ever seen a dct temp warning even when engine oil temps were at the 130+ degC range so definitely something abnormal with yours. I would do a dct adaptations reset and also change the DCT temp sensor first.

Originally Posted by jp1984

I will check this for ya tomorrow too.

Originally Posted by amrazM

That sensor is part of the gearbox, it’s not serviceable.

My heat exchanger for the DCT was warm to the touch after backing out of my driveway and driving for 10 minutes. The dct uses coolant from the heads which passes through a heat exchanger mounted on the unit.

Op if you really want to explore this issue you should consider logging your dct temps. It shouldn’t be too far off from the coolant temps when the car starts. My last few dct services when the weather was in the 60s F the dct temp usually hits 90F in about 2 minutes which is when the thermostat opens.

Thanks a bunch for reply guys. So seem its correct that cooler should be warm pretty soon, thats a start.

Yep I'm aware of that DCT fluid is pre warmed by coolant, been thinking about the aux pump code (A6D1) here but concluded it doesn't correlate with the DCT heat code.

So the DCT tstat opens already at 90F/32C?? (tstat btw replaced recently). Reading about temps well over 120-130C. Only have Carly and haven't been able to read the DCT temo myself though but again the heat exchange is warm to assumingly well over 32C.

Hmm, if I could conclude that the error comes from actual over heat rather than sensor issue only. Which as mentioned needs DCT out to replace anyhow... Box adaptaion "should be" reset after last service, but will re adress this with the shop.

I may add that my DCT incl cooler and lines was replaced new a few years ago, with currently about 30k miles on it.

[deansbimmer]

As these cars are starting to age and see higher miles we are dealing with more and more of these. In years past the DCT overheating errors were pretty obviously correlated with the driver or vehicle (supercharged etc), but now we see these with daily drivers and not necessarily high milers.

It's easy to diagnose basic issues caused by fluid levels, blockages, thermostats, etc. Once those preliminaries are out of the way, the combination sensor in the clutch housing may be faulty. It usually stores a plausibility fault however (self references against the second temp sensor in the mechatronics) but not always.

As the last culprit, and the one we're starting to see more and more- the clutches need to be replaced to eliminate the fault. We've replaced clutches which showed no discernible wear which resolved the overheat faults.

When we quote these- we quote the clutch and the combination sensor, and full filter/reseal job while it's out. Any remedy- must be followed up with the appropriate software actions.

[Redd]

Originally Posted by deansbimmer

As the last culprit, and the one we're starting to see more and more- the clutches need to be replaced to eliminate the fault. We've replaced clutches which showed no discernible wear which resolved the overheat faults.

Thanks for the detailed reply deansbimmer. Any idea why clutches with no wear would cause fluid to overheat? Could they be warped and therefore causing unnecessary friction?

[Helmsman]

Originally Posted by deansbimmer

As these cars are starting to age and see higher miles we are dealing with more and more of these. In years past the DCT overheating errors were pretty obviously correlated with the driver or vehicle (supercharged etc), but now we see these with daily drivers and not necessarily high milers.

It's easy to diagnose basic issues caused by fluid levels, blockages, thermostats, etc. Once those preliminaries are out of the way, the combination sensor in the clutch housing may be faulty. It usually stores a plausibility fault however (self references against the second temp sensor in the mechatronics) but not always.

As the last culprit, and the one we're starting to see more and more- the clutches need to be replaced to eliminate the fault. We've replaced clutches which showed no discernible wear which resolved the overheat faults.

When we quote these- we quote the clutch and the combination sensor, and full filter/reseal job while it's out. Any remedy- must be followed up with the appropriate software actions.

Thanks mate. Wonder why new clutches would solve the issue, specially if the original comes out in fair shape. What about clutch timing/alignment, do you know anything about how that works and is performed?
My DCT has had a very comfortable life, simply can't be any kind of natural wear. But the clutches doesn't behave the way they should, it would be a different story.

Thanks

[deansbimmer]

Clutch travel in these DCT's is very minute. It doesn't take much of a discrepancy between a new clutch and a worn clutch to cause issues. Learned adaptations can only compensate for so much. We have measured and evaluated the clutch stacks between various problematic clutches and new clutches and not found much difference. Visually, they may even be identical.

Yes, warped or compromised steel discs will certainly cause issues, but problems may also stem from seemingly innocuous culprits like glazing or surface condition of the steel plates and friction discs. Perpetually babied transmissions can in theory cause problems too, just as brake rotors can suffer from pad buildup and vibrations from never getting hot enough.

Clutch engagement points, learning of pressure curves, adaptations, etc are important points of reference for the controller. During service or diagnostics, these software aspects are treated with the same importance as the physical remedies being performed to the DCT. ISTA diagnostics and ABL's are essential when attempting to treat customer concerns.

[Helmsman]

Originally Posted by deansbimmer

Clutch travel in these DCT's is very minute. It doesn't take much of a discrepancy between a new clutch and a worn clutch to cause issues. Learned adaptations can only compensate for so much. We have measured and evaluated the clutch stacks between various problematic clutches and new clutches and not found much difference. Visually, they may even be identical.

Yes, warped or compromised steel discs will certainly cause issues, but problems may also stem from seemingly innocuous culprits like glazing or surface condition of the steel plates and friction discs. Perpetually babied transmissions can in theory cause problems too, just as brake rotors can suffer from pad buildup and vibrations from never getting hot enough.

Clutch engagement points, learning of pressure curves, adaptations, etc are important points of reference for the controller. During service or diagnostics, these software aspects are treated with the same importance as the physical remedies being performed to the DCT. ISTA diagnostics and ABL's are essential when attempting to treat customer concerns.

Many thanks again Deansbimmer. Dealer claimed they did reser adaptation and performed learning (how ever that is done), but these particular guys failed on claimed work before.
Your input on glazed surfaces is interesting, as daily driver my poor M3 seldom see proper driving, in fact when I do drive hard the code never popped up. Guess I need to make time to take her out on the back roads more...

I'll have another go with the indy who replaced DCT tstat and fluid last year, and report nack.

Thanks again
Nik

[spammysammich]

Hopefully a good old fashioned Italian tune up is just what the doctor ordered.

[roastbeef]

there is a heat exchanger that i think also acts as a thermostat for sending fluid to the cooler. i'm not sure how it actuates or the complete function, but if you're getting dct overheating problems and your bumper heat exchanger isn't hot to the touch, i would imagine something is wrong with this thermostat device. i don't have first hand experience with this, but if that is how this device functions and those are your symptoms, i'd imagine it has something to do with it.

https://www.realoem.com/bmw/enUS/sho...diagId=17_0437

[Helmsman]

Originally Posted by roastbeef

there is a heat exchanger that i think also acts as a thermostat for sending fluid to the cooler. i'm not sure how it actuates or the complete function, but if you're getting dct overheating problems and your bumper heat exchanger isn't hot to the touch, i would imagine something is wrong with this thermostat device. i don't have first hand experience with this, but if that is how this device functions and those are your symptoms, i'd imagine it has something to do with it.

https://www.realoem.com/bmw/enUS/sho...diagId=17_0437

Cheers Roastbeef,
oil/air exchanger does get warm. Mentionen regularor/Tstat for coolant/oil exchanger is replaced. I've been thinking about the aux coolant pump in the realoem diagram, but concluded that doesn't seem to be the issue.
Just had the DCT reset again the other day. Will drive away for a bit and see what happens.

[Eileen]

I have a 2013 135, low, miles (55,560). The DCT temp indicator came on amber and immediately switched to red and shut off my car. I waited a minute, started the car and it ran fine. I was not driving the car hard. It was around the town.

I took it into a BMW dealer and they claim its a water pump issue. That does not make sense to me as my understanding is the DCT transmission cooling is separate. Can anyone advise me here?

[B8bydesign]

Originally Posted by Eileen

I have a 2013 135, low, miles (55,560). The DCT temp indicator came on amber and immediately switched to red and shut off my car. I waited a minute, started the car and it ran fine. I was not driving the car hard. It was around the town.

I took it into a BMW dealer and they claim its a water pump issue. That does not make sense to me as my understanding is the DCT transmission cooling is separate. Can anyone advise me here?



Attachment 2958606

You'll probably have better luck asking this over on the 1 series forum: https://www.1addicts.com/forums/forumdisplay.php?f=229

[Eileen]

thx

[DrFerry]

Originally Posted by Helmsman

Hi fellow DCT owners, been having the friggin heat code coming and going for years now. Fluid, filters, adaptation reset etc, no result. Typically turns up after short runs like 8 miles very calm/low rpm from office, even before the engine is at full temp. Goes away after some careful driving. Favor I'd like to ask: Could you stick your hand under the bumper and feel whether your DCT fluid heat exchanger is hot already after shorter runs? Mine is but I have no clue whether it should already after such short driving. If not, it is probably the sensor doing its job, but I so far tend to believe the sensor is playing tricks on me. Many thanks in advance! Nik

Perhaps you've already solved this issue, but clutch disc slip - or DCT clutch pak slip - comes to mind. The DCT basket holds 8 discs if I recall correctly. Imagine if one or more of the clutch disks are not properly disengaged while stationary (with foot on the brake) during your short trip warm up phase? Heat would be generated. Just one more thought... Your profile says "Sweden" so I have to ask do you live in a hilly area where on short drives the clutch pack might slip while going uphill? These are the miscellaneous ramblings of a late middle aged man.. Just my two cents and probably explains what deansbimmer mentioned is now happening with older cars i.e. the DCT clutches are worn and hence slip. I replaced my DCT clutches at ~65K miles with the SSP Spec-R pack. BPMSport Mike B' at BPMSport sells the SSP cooling kit and clutch disc pack. EAS also sells the clutch discs.
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https://www.bpmsport.com/services/ss...g-package.html
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https://www.bpmsport.com/ssp-clutch-package.html
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https://europeanautosource.com/ssp-s...-vehicles.html
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[spammysammich]

If I recall correctly changing his aux water pump tamed the problem.

[Redd]

Originally Posted by DrFerry

Perhaps you've already solved this issue, but clutch disc slip - or DCT clutch pak slip - comes to mind. The DCT basket holds 8 discs if I recall correctly. Imagine if one or more of the clutch disks are not properly disengaged while stationary (with foot on the brake) during your short trip warm up phase? Heat would be generated. Just one more thought... Your profile says "Sweden" so I have to ask do you live in a hilly area where on short drives the clutch pack might slip while going uphill? These are the miscellaneous ramblings of a late middle aged man.. Just my two cents and probably explains what deansbimmer mentioned is now happening with older cars i.e. the DCT clutches are worn and hence slip. I replaced my DCT clutches at ~65K miles with the SSP Spec-R pack. BPMSport Mike B' at BPMSport sells the SSP cooling kit and clutch disc pack. EAS also sells the clutch discs.
.
https://www.bpmsport.com/services/ss...g-package.html
.
https://www.bpmsport.com/ssp-clutch-package.html
.
https://europeanautosource.com/ssp-s...-vehicles.html
.

.

.

How's your experience with the SSP clutches? Any NVH? Would you recommend them over stock clutches for a daily driven car?

[DrFerry]

Originally Posted by Redd

How's your experience with the SSP clutches? Any NVH? Would you recommend them over stock clutches for a daily driven car?

The SSP clutches have performed flawlessly for 55K miles in my car so far. The only NVH I ever notice is on wet, cold and humid days there is a critical RPM upshift point when shifting from 2 to 3rd (always those gears) around 3500RPM where I hear a momentary sort of distant "bark" sound (like a puppy stuck in the trunk - I kid you not). It's a brief sound (less than a second). When the DCT shifts from the 2nd to 3rd the baskets switch clutches between layshafts. Consequently, I think the friction material at that exact critical speed makes the bark noise -> as some slip naturally occurs. I have often wondered if it was a function of not using the SSP billet clutch baskets but their disks are made to fit the OEM baskets. It's not a big deal really, and only happens on very rare occasions. Hence, I never addressed it.

Other than the tiny NVH mentioned above, the SSP Spec-R has been a great upgrade to the OEM DCT gearbox and is rated at holding around 900 ft-lbs or torque. When combined with the HARROP blower, Drag Radials and the lower ring and pinion it was the tires that were the traction limitation and not the the clutch.
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https://sspperformance.com/shop/ols/...ormance-clutch
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My experience has been that the SSP Spec-R clutch was better than OEM in a high torque application with no real discernible difference in NVH. However, without a big increase in torque from a blower or turbos, I don't think the SSP Spec-R is really necessary for a stock or full bolt on car. SSP makes a tamer version of its BMW DCT clutch pack (called the Spec-S) and it will probably be of equally high quality IMO.
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https://sspperformance.com/shop/ols/...ormance-clutch
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https://sspperformance.com/shop/ols/...es/bmw-7dci600
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Hope this helps. There's some more information on the forums possibly in the "Official Harrop" thread on this subject.

[Scrippy]

Helmsmen,

I feel heat pretty quick on my DCT. I've never had the heat issue pop up on the dash and I've got 244,xxx miles. I currently have a vibration on hard acceleration in 1st gear that has been diagnosed as a flywheel issue. I'm having it and the clutch packs done. Question…..do you have that tick out of your car/motor/whatever at idle when up to temp? It's erratic but definitely noticeable. Reason I ask is I've been wondering what it's cause is for years. I'm wondering if it's flywheel play relative to its axis of rotation. If good looking but old clutch packs create heat potentially could this be the audible result of that or the other?

[Helmsman]

Originally Posted by Eileen

I have a 2013 135, low, miles (55,560). The DCT temp indicator came on amber and immediately switched to red and shut off my car. I waited a minute, started the car and it ran fine. I was not driving the car hard. It was around the town.

I took it into a BMW dealer and they claim its a water pump issue. That does not make sense to me as my understanding is the DCT transmission cooling is separate. Can anyone advise me here?



Attachment 2958606

Hi Eileen,

interesting input. I have had the DCT heat issue over years and long story short believe I've finally solved by replacing the (aux) water pump which I assume your dealer refer to.
Went to couple of different shops incl main dealer who had no clue and could not comment on my thoughts about the pump. Congrats, you seem to have found a BMW dealer who actually knows its products!

See this thread for further details. Let me know if you can't access the tech desciption ref to and I'll post it separately: https://www.m3post.com/forums/showthread.php?t=1772232

Ps. Its a 220 Euro part, very easy to replace yourself.

Cheers,
Nik