DCT Transmission gear slip

[SeattleJerez]

Hello everyone,

I own a 2009 DCT ESS 625 M3. I've had the car for about 18 months, and bought it at 20k miles. It has 35k on it today. It was a garage queen prior to my purchase, owned by an older gentleman that didn't beat the car. When I got it, I was young(er) and more immature, and I launched it 10, maybe 15 times in the first 3 months I owned it. Not proud of this, but want to give you all the info.

Now before I had the ESS 625 kit installed, sometimes under high torque around 6-7k rpms and above, and often times when switching gears under torque 1-2-3, I would experience what sounds like clutch slip. It's a distinctive sound, the best I can describe it is the sound of a steel cable being very quickly pulled across another metal object. Maybe the sound of a steel cable unspooling. The power loss when this happens is fairly noticeable.

After the ESS 625 kit, sometimes it's better, sometimes it's worse. Under high torque, again around 6-7k RPMS, I hear the clutch slip, it struggles to shift under torque, but eventually finds the gear and clicks in.

I'm curious if anyone else has had any sort of similar issues with/without a SC kit installed, and if there are any other recommended fixes/advice to the issue.

The advice I've been given is:

1. GTS software update, currently in the works
2. Replace the gear cluster (expensive and time consuming)

[dparm]

I feel like the GTS software is only going to accelerate wear...

[burnrbr]

From what I've read, early M3 DCT factory tunes had lower pressure to the clutches than later ones. Somewhere around 2011 things changed. You might want to consider a BPM DCT tune. He can adjust the clutch pressure to prevent slippage, but you may have already damaged your clutches. BMW uses the same DCT clutches in most of their cars including the new M5 which has a lot more torque than your supercharged M3. Therefore, the clutches can hold the power; the DCT tune needs adjusting.

[SeattleJerez]

Sounds good, from the prices I've read of BPM tunes, they are 10-15x more expensive than the GTS software update. Any idea if the GTS software adjusts pressure? Considering GTS was after 2011, I would assume clutch pressure is part of the software update.

[burnrbr]

I'm personally up in the air about the GTS software as some of the available information isn't definitive. It is a clear upgrade in shift speed and a bit smoother for shifts in the lower gears when coming to a stop. But, I've read it can overheat your DCT if you use the GTS tune that does shifts in 90 mls. The recommendation is to use 100 mls shifts to prevent overheating or upgrade your DCT cooler. I haven't found multiple versions of the stock GTS tune so it's either a myth or the 100 mls version is from a tuner. A local buddy of mine can hook me up with the GTS tune for free, but I'm not sure I should because I do track my M3 and I don't want to upgrade the DCT cooler right now. Maybe someone can chime in and share some definitive information on either the 100 mls shift speed version or the lack of overheating when tracking hard with the stock GTS tune.

[dparm]

Why would the GTS tune cause overheating? I don't know about you guys, but when I'm at the track it's not like I'm shifting every 2 seconds. For most tracks I can leave the car in 2nd and 3rd gear for the vast majority of the lap.

[jzyaa]

I have same issue. what is BPM tune?

[jzyaa]

can i change clutch pressure by flashing ESS DCT transmission software?

[dparm]

Originally Posted by jzyaa

I have same issue. what is BPM tune?

http://www.bpmsport.com/

[SeattleJerez]

Figured I'd post my resolution.

I went for the GTS DCT software update. I've only put maybe 30 miles on it, but I couldn't get the transmission to slip if I tried. Shift times are nicer, no *waiting, waiting, waiting, CLUNK* for reverse. I believe it may have even been patched in the newer transmission software, but I wanted the GTS anyway. Feels smoother, I believe they should have come out of the factory like this. Hopefully that helps someone having a similar issue.

[dparm]

Originally Posted by SeattleJerez

Figured I'd post my resolution.

I went for the GTS DCT software update. I've only put maybe 30 miles on it, but I couldn't get the transmission to slip if I tried. Shift times are nicer, no *waiting, waiting, waiting, CLUNK* for reverse. I believe it may have even been patched in the newer transmission software, but I wanted the GTS anyway. Feels smoother, I believe they should have come out of the factory like this. Hopefully that helps someone having a similar issue.

It has not been patched in newer software, as far as I know. My car has 241E and a bunch of other updates from this past summer, and it's the same as it was when I was on older software.

[SeattleJerez]

Huh. Well that's good to know, that this was the exact update I needed. It smoothed out all my problems.

[tlow98]

Originally Posted by dparm

Why would the GTS tune cause overheating? I don't know about you guys, but when I'm at the track it's not like I'm shifting every 2 seconds. For most tracks I can leave the car in 2nd and 3rd gear for the vast majority of the lap.

Same amount of work in less time = more heat?

Just venturing an educated guess, not being a smart ass.

OP, look forward to hearing your results in a thousand miles or so.

[Sneaky Pete]

Originally Posted by tlow98

Same amount of work in less time = more heat?

I would have thought that the heat generated is an effect of the clutch plates slipping against each other...so less time slipping should equal less heat generated.

[dparm]

Originally Posted by Sneaky Pete

I would have thought that the heat generated is an effect of the clutch plates slipping against each other...so less time slipping should equal less heat generated.

Not arguing with the physics of it, but we are talking about adding or removing tens of milliseconds, followed by long periods (many seconds) of no clutch movement.

In other words, you are possibly generating more heat for 10-20ms, but then the car is running up through the revs for 5000ms (5 seconds) or more. Some of the extra heat is bled off over during that time.

Again, this is just speculation.

[Sneaky Pete]

On further consideration...if the GTS software is forcing the DCT oil pump to raise the oil pressure in order to increase the clamping force on the clutch packs then that will be most likely be the cause of any elevated DCT oil temp.
Noting that the DCT oil pump runs continuously whenever a gear and a clutch is engaged
As you increase the compression on a liquid its temperature rises all else being equal.

[Patrón]

Originally Posted by SeattleJerez

Figured I'd post my resolution.

I went for the GTS DCT software update. I've only put maybe 30 miles on it, but I couldn't get the transmission to slip if I tried. Shift times are nicer, no *waiting, waiting, waiting, CLUNK* for reverse. I believe it may have even been patched in the newer transmission software, but I wanted the GTS anyway. Feels smoother, I believe they should have come out of the factory like this. Hopefully that helps someone having a similar issue.

can you please be specific with what gts dct software update you received? where did you purchase it and who uploaded it? online vendor or local bmw dealer?

[Patrón]

bump

[R_lara]

Curius about this.

[dparm]

Originally Posted by Patrón

can you please be specific with what gts dct software update you received? where did you purchase it and who uploaded it? online vendor or local bmw dealer?

Dealers do not install GTS software. That car wasn't even sold in North America.

Tread lightly when it comes to "GTS software", as a lot of people claim to flash it...but you are not getting the real deal, or you are getting some modified version of it.