E92 M3 DCT Overheat!

[dyansamuel]

I got a yellow warning signal on the dash as well as on the iDrive screen saying the temperature is high, avoid starts and stops or driving at walking speed, but can still drive. It happened after 10-15 mins in the traffic jam.

This signal has come up overtime the car crawls slowly in traffic. I have changed the gearbox fluid but it didn't seem to help. Anyone got any clues on this?

Thanks

Updated 12-24

Today I took my car in a workshop and had the DTC control unit and the clutch plates re-calibrated.

After the re-cal, overheating is completely gone. The clutch and the gearbox oil maintain at normal temperature even after a long time of hard driving.

The problem is, after a considerable time of use, the clutch plates are no longer at the right positions so they keep grinding each other excessively. Changing the gb oil would not change the spacing of the plates. The re-cal is definitely necessary to put the plates back into right positions.

[kenwelch]

DCT limitations are covered about page 49 in the owners manual. You will find several helpful tips in that section.

You can deactivate Low Speed Assistant by braking to a full stop.
Also there is a warning not to ride the brake pedal while using Low Speed Assistant.

This is the same as a manual transmission clutch except that it is cooled by the transmission fluid and the temp sensor is able to warn us about an over heat condition. When the Low Speed Assistant is being used the clutch is slipped to allow the vehicle to move slowly in stop and go traffic. With a manual transmission clutch you would fully release (pedal down) most of the time and not slip the clutch on hills to prevent rolling backward. Full release is achieved by a full braking stop with the DCT system.

[dyansamuel]

Originally Posted by kenwelch

DCT limitations are covered about page 49 in the owners manual. You will find several helpful tips in that section.

You can deactivate Low Speed Assistant by braking to a full stop.
Also there is a warning not to ride the brake pedal while using Low Speed Assistant.

This is the same as a manual transmission clutch except that it is cooled by the transmission fluid and the temp sensor is able to warn us about an over heat condition. When the Low Speed Assistant is being used the clutch is slipped to allow the vehicle to move slowly in stop and go traffic. With a manual transmission clutch you would fully release (pedal down) most of the time and not slip the clutch on hills to prevent rolling backward. Full release is achieved by a full braking stop with the DCT system.

Thanks!!

[dyansamuel]

Today I took my car in a workshop and had the DTC control unit and the clutch plates re-calibrated.

After the re-cal, overheating is completely gone. The clutch and the gearbox oil maintain at normal temperature even after a long time of hard driving.

The problem is, after a considerable time of use, the clutch plates are no longer at the right positions so they keep grinding each other excessively. Changing the gb oil would not change the spacing of the plates. The re-cal is definitely necessary to put the plates back into right positions.

[kenwelch]

The "Clutch Adaptation" does not re-position the clutch plates, but sets the engagement points for both clutches in the control module. The is done by monitoring clutch fluid pressure when applying the clutch pistons. The engagement points are then saved to adaption memory.

The Oil Calibration may have been also helpful because of it's relationship to fluid cooling.

This is from the technical manual:

"Service Functions
The following Service Functions are currently available on the
BMW diagnostic equipment (GT1 Tester) for the M DCT transmission:
• Clutch adaptation
• Transmission adaptation
• Oil calibration
• Parking lock hook test"

You can read about these in the technical manual starting on page 50.
http://www.m3post.com/forums/attachm...hmentid=587904

[warrior3313]

Originally Posted by dyansamuel

Today I took my car in a workshop and had the DTC control unit and the clutch plates re-calibrated.

After the re-cal, overheating is completely gone. The clutch and the gearbox oil maintain at normal temperature even after a long time of hard driving.

The problem is, after a considerable time of use, the clutch plates are no longer at the right positions so they keep grinding each other excessively. Changing the gb oil would not change the spacing of the plates. The re-cal is definitely necessary to put the plates back into right positions.

dyansamuel,

How much did that re-calibration cost you? I got the same DCT Trans Temp Warning last night and I believe I need to have this done to mine.

[JDM_CL9]

Sorry to bump an old thread but I think I am having the same problem.

Can this only be done by BMW Dealer?

[mdm9]

Also interested

[deansbimmer]

Its worth mentioning, but some DCT M3 have a block off plate on the trans cooler that blocks off half of the incoming air flow. It may be part of a cold weather package or just an add-on for northern climates to prevent overcooling, but if yours has that plate it could be preventing your cooler from operating at the necessary 100% for your climate.

Just look into the passenger side bumper duct and see if there is an aluminum plate there. If not then disregard this message, the posters above are on the right track

[Leonardo629]

Originally Posted by deansbimmer

Its worth mentioning, but some DCT M3 have a block off plate on the trans cooler that blocks off half of the incoming air flow. It may be part of a cold weather package or just an add-on for northern climates to prevent overcooling, but if yours has that plate it could be preventing your cooler from operating at the necessary 100% for your climate.

Just look into the passenger side bumper duct and see if there is an aluminum plate there. If not then disregard this message, the posters above are on the right track

I think you are talking about the right bumper air duct, manual cars get a duct with a block off plate, DCT cars don't.

[JDM_CL9]

Interesting - I will take a look when I get home if my car has this block off plate.

[deansbimmer]

Originally Posted by Leonardo629

I think you are talking about the right bumper air duct, manual cars get a duct with a block off plate, DCT cars don't.

I think you're right. I have however, still worked on DCT cars with the block off plate over the cooler so I thought it was worth mentioning.

[Leonardo629]

That's weird, unless it was fitted the wrong duct at the factory, or the car had frontal damaged, and the shop simply ordered the wrong duct.

6spd manual duct


DCT duct

[JPSurratt2005]

I recieved the yellow cog warning last year and ended up cleaning the DCT cooler with coil cleaner. I also used a small gasket pick to straighten any bent cooling fins.

A few weeks ago I had the same yellow warning pop up again. This time I replaced both filters and drained and filled 6L of fluid.

So far it's running great and shifting better than before. I'm also not getting that harsh downshift to 2nd when coming to a stop. It's much more composed and doesn't jerk the drivetrain.

[trebm3]

Originally Posted by JPSurratt2005

I recieved the yellow cog warning last year and ended up cleaning the DCT cooler with coil cleaner. I also used a small gasket pick to straighten any bent cooling fins.

A few weeks ago I had the same yellow warning pop up again. This time I replaced both filters and drained and filled 6L of fluid.

So far it's running great and shifting better than before. I'm also not getting that harsh downshift to 2nd when coming to a stop. It's much more composed and doesn't jerk the drivetrain.

What fluids did you go with and where did you buy filters?

[Route 16]

Originally Posted by trebm3

What fluids did you go with and where did you buy filters?

interested to know too but my symptoms are skipping gears, suspected to be low fluid after the last trans drain and fill

[trebm3]

My issue is very weird. It only happens to me in manual mode and when I’m blipping revs. If I’m in auto no clutch overheat lights, regardless of how hard I’m driving. I feel like it may be a sensor issue for me.

[JPSurratt2005]

Originally Posted by trebm3

What fluids did you go with and where did you buy filters?

I bought it at ECS, however the cartridge filter in this kit is not for out DCT. I emailed them about it but was ignored. It has a lip on the end that our filter doesn't have, and I had to dremel it off in order to get the cap back on and the snap ring in. Major pain in the a$$ mostly due to not knowing why it wouldn't fit the first 5 times, until I compared it with the stock filter.


They sell the correct filter here unless you feel like saving money and using a dremel.

Sorry for the late reply, I really need to turn email notifications on.

[JPSurratt2005]

UPDATE: Fluid, filter change didn't fix it. I've had both DCT warnings in the summer, winter, driving slow, driving fast, etc. I've checked the cooler temp with a temp gun during the warning and only read around 130F.

In another thread people have stated having electrical fault issues related to the engine ground strap. Mine didn't look bad but I replaced it anyway and I have not had any DCT faults since. That was about a month ago and it has been super hot here in Oklahoma.

I'll update this post if I get anymore faults. For $50 and about 30 minutes of work I really hope it was my issue.

[deansbimmer]

Fluid and filter change will rarely if ever resolve high temps, unless the fluid level was low. The fluid bears the thermal load so if it's low it doesn't have the ability to maintain cooling.

Check the faults and see which ones are stored. If it's temperature stage only, the combination sensor (temp/rpm) inside the bellhousing may require replacement. Ista-D has test plans for this.

If there are over-temp faults combined with shift shaft faults, expect clutch failure.