transmission slip
 

Going to start a new thread in hopes that someone can verify this does it does not happen with their car.

Having this issue with my '14 507 with 16,000 miles. Only mods are row boxes with afe dry flow filters and deleted second cats. Im having what appears to be a slip or flare between the 1-2, 2-3 and 3-4 gear change under partial throttle ONLY after the vehicle has reached normal operating temperature. Doesn't happen when the car is cold. The rpms flare about 200-400rpms right as the shift occurs, it goes to the next gear smoothly and quickly with no jerking, banging or bogging.

At first, this was happening in C, S and S+. Went to the dealer and took the tech for a ride to confirm the problem. First, they found no codes. They did a shift point adaptation relearn but the computer would only allow the relearn to be done in C. They also updated the tcu software. Got the car back and it no longer happens in C BUT still happens in S and S+. Took it back again and they did a wet clutch relearn. The computer allowed the wet clutch relearn in C and S Mode. Got the car back again and it still happens in S and S+ only just like before. I just recently realized it only happens when the car is fully warm and theres a very small window of throttle position for the slip to occur. That's why the dealer was unable to produce the problem and gave me the car back. But I can produce the problem anytime I want. This never happens under light throttle or wot. Only partial throttle.

I have 2 videos showing the problem.

Can anyone with a 7g mct tell me if they have ever noticed something like this happen? If not, can you guys with the mct trans try to make your trans do this. Select S mode. Once the car is fully warm, oil at 220f, ease into the throttle with enough pressure that would make your car typically shift around 2500 rpms and see if the rmps flare up a few hundred more rpms before completing the shift. Even when I do this, it doesn't happen 100% of the time. Sometimes takes a few tries.

Watch the rpms right around 2600 when the car attempts to shift from 3 to 4 and the tach jumps to 3000 before completing the shift
https://youtu.be/CW-mA_-cBOg

In this video it happens in every gear but is most noticeable in the 3-4 gear change around 2700
https://youtu.be/bC7dKdR1mYk

The tech is going to reach out to the shop foreman in hopes of replacing the valve body but he said its very hard for that to happen if there's no codes stored. I've checked dealers within 50 miles to see if they have the same car for sale and I would go do a test drive but no luck

My car is being wrapped in PPF, so I don't have it right now. Otherwise, I would have tried. I only have 4,600 miles on mine, so it probably would be a good reference... If no one responds by the time I get mine back, I'll give it a shot for you.

i dont see anything wrong with the car in the videos you posted. It's an automatic not a dual clutch, that is definitely not a flare of any sort.

I see what you're talking about, and no, I've never noticed it on any other W204 C63 I've driven. There's another possibly unusual behaviour - the 3 -> 4 shift in the second video happens much too soon after the 2 -> 3 shift... are you manually shifting or doing something with the accelerator? I would expect the car to hold a gear longer and pick up some speed in each gear before it upshifts, which is notably absent. The speedo needle barely moves as you go from 2nd to 3rd to 4th.

If it's not shift point adaptations and happens all the time, I would tend to think that the transmission fluid is not under sufficient pressure to actuate the clutches when it should. It could be an issue with the TC valves / solenoids or even the fluid itself. If it's only noticeable on the 3 -> 4 shift, that's the K2 clutch.

Thanks

The videos are definitely not the best way to show the issue. A ride in the car is the way to go but that's the best I could do. Maybe flare isn't the correct word but there is certainly a surge in the rpms right as the shift is about to occur.

"are you manually shifting or doing something with the accelerator?" I'm not manually shifting but the possible explanation for the quick gear change is me reducing throttle pressure to specifically show the surge in rpms before the shift. Like I said, this surge only happens under a small window of throttle position.




As far as fluid and pressure is concerned...if I recall correctly, the tech told me that they had the computer/machine (whatever its called) used to check the fluid and flow. He said it was all within spec. I believe its on my invoice so Ill have to check that


Iif any of those scenarios you suggested were actually the case, wouldn't you think a code would show?

I am curious if you discover the cause or solution to this. I think I have the exact same issue. I have a 2012 C63 with about 50k miles. This behavior started (or I started noticing) right after I had the 40k trans service. At the same time I also had the engine ECU flashed back to stock. The car had a tune from a previous owner and I wanted the car back to stock.
Symptoms I have observed:
1. The rpm flare is less than a gear change and almost feels like the amount of rpm change one used to feel in the 90's with the early lock-up torque converters.
2. It seems to only happen or be noticed in the higher gears at moderate throttle around 2000rpm.
3. It happens in all trans modes including manual for me.
4. It never happens under aggressive driving.

The last point makes me think nothing is wrong mechanically as I assume it would show up under aggressive use. Rather I assume it is some kind of computer glitch that causes the transmission to feather the clutch engagement.

Just my experience and guesses. I will follow the thread to see if anybody comes up with something to solve.

Thanks.

I have noticed the same thing after the EC v5 tune. I didn't think it was a problem until you mention or it isnt?
Mine is a PF though.
I noticed it happen at partial to lightly heavy throttle. My thought is, this has to do with the timing of the heavy throtle and the decrease in throtle.

our syptoms seem to be rather similiar with only minor differences. My car will be going back to the dealer in the near future in hopes of solving this

Eurocharged sent me a new v6 file since my tcu software was updated. I loaded the v6 into the car a few days ago and I can say without a doubt that this tune makes this pre-existing rpm surging much more noticable. I hate to say it makes it worse but it really does. The surging that was no longer present in C mode with the stock tune is now surging in C mode ever so slightly. Since everyone here and even eurocharged says they dont touch the tcu maps, I just dont understand why this tune makes this shifting issue so much worse.

The throttle response does change how the transmission react。Even there is no tcu tune.

bentz69 - your previous posts said nothing about the car having an aftermarket tune ("Only mods are row boxes with afe dry flow filters and deleted second cats."). If it has been molested by an aftermarket tune, I would suggest you go back to EC and get them to deal with it instead of wasting everyone's time and/or trying to pass it off as a warranty issue. :rant:

The car was experiencing this problem before the tune was ever applied (or atleast I think it was but cant be 100% sure). After the tune was installed, I started to really notice this problem much more frequently and brought it to the attention of EC who said it wasnt the tune.

read this thread
https://mbworld.org/forums/c63-amg-w...-problems.html

Long story short, i only noticed these shifting problems after the tune was applied. I flashed back to stock and the problem was still there.

So it is a warranty issue

Uh huh. Try telling that to Mercedes. Not sure there was a problem before tune ("only noticed these shifting problems after the tune was applied"), now definitely a problem after tune. You can bet they'll check your ECU if you ask them for a new transmission or there's some other significant repair "under warranty". Good luck.

not worried about that but thanks :y

can anyone list all the other benz models that use the 7g mct?

Google

Another unhelpful and pointless post. You spend way too much time going through all the threads attempting to tell people to search and making useless comments instead of trying to help people. Maybe your definition of a forum to ask questions is different then everyone else. SMH

Go ahead and make your reply about all the new guys who don't search and make pointless threads when a search would suffice lmao

I said that because I Googled your question word-for-word and had a comprehensive answer in less than 3 seconds, genius. I was trying to help, go **** yourself and your entitled attitude.

You're the one who's entitled.... in every thread. Watch out, the Google POLICE is here. Guy must have a lot of stocks in search engines or something.

**** this guy.

Hi Stinky I missed you :wavey:

Er - no. It is not a warranty issue. Your argument is exactly the same as me saying "Your nose wasn't bleeding. I then started punching you in the face and your nose started to bleed. However, then I stopped punching you and your nose was still bleeding, so it couldn't have been the punches to your face that made your nose bleed." I hope you realize how ridiculous your arguments is.

You f___ed with it, which screwed something up in the process. Don't expect MB to come to your rescue and spend their time and money to replace whatever it is that your aftermarket tune broke. MB never said that their car would work with someone else's tune - in fact, they say exactly the opposite. Ask EC to fix it and stop wasting everyone else's time.

wow....whats with the all butt hurt people around here? this place is crazy lol

Ill say it slower for you. Im NOT positive whether or not the problem was there BEFORE the tune was applied. It very well could have been there but I started to notice the problem AFTER the tune was applied. BUT, and theres a big BUT, I flashed back to stock and problem is still there.

If the stock tune was flashed back to the ecu and the problem still persists BUT not nearly as severe while the EC tune was there, who are you to say it wasnt there in the first place?

And yea, I do expect MB to come to the rescue and fix a problem that persits even after the oem tune is on the car.

You seem very knowledgable, would you happen to know if there would be any changes to the car that would NOT go back to stock after the original tune is flashed back to the car. EC says no

I think they are trying to explain to you that if you didn't notice a problem while stock, flashed to a tune and then something broke while it was tuned, the problem would still persist after you flash back to stock. That also suggests that something happened because of the tune, which is not MB's fault and they shouldn't have to warranty you. You put a tune on the car and that broke something.

I'm not saying that is what happened... just trying to explain their point.

Above, Jay Rick said "I have noticed the same thing after the EC v5 tune. I didn't think it was a problem until you mention or it isnt?"

This does seem to tie the problem to the EC V5 tune . . .

Jim G

This thread and the previous throttle hesitation ones makes me think twice about pulling the trigger on a Eurocharged tune. I've used Eurocharged before on our S65 AMG with no problems, but definitely don't want to run into this issue on the BS. Still debating if a tune is even worth it or not on the BS models?