Hello guys,
I have a C43 Coupe Facelift, with around 135.000 km now. I have owned it for a year now, put over 30.000 km in it, and for half a year now, when the engine is cold, the first shift between 3-4 sounds like its slipping. If i gently accelerate, the revs go up as it shifts, but after this first case of this, it's normally fine. If i accelerate not gently, just firmly, then it's okay, but still not perfect. When the car is warm, around 60+c for the trans, it's mostly fine. HOWEVER, i must also add: When not giving enough gas, sometimes the shift feels really weird, like it punches the gear into 4th with a big jerk. This doesnt happen all the time, but with more firm gas normally the shifting is fine.
Also, whenever the car automatically downshifts, 4->3->2, i hear bubbling or sort of burbling, but not from the engine or exhaust, more kind of from the transmssion. It's not crunchy, it's not metal sounding, it's more fluid i think.
The fluid was changed over 15.000 km ago, with a TCU reset via a Mercedes authorized workshop.
Anyone experience similar?

 

Do you have any videos? And are you tuned by any chance? I have a pre face lift that is tuned and I'm currently having issues with my up shift from 3rd-4th gear as well.

 

Oh, I’m bone stock. Completely scared to tune my car if my trans is toast…
I’ll try and get a video out here tomorrow

 

Okay yeah definitely a bit concerning. I have a video I’ve attached let me know if that’s what occurs when you up shift.

 

My 2020 C43 AMG S205 does exactly the same going from 3rd to 4th and it only have 26000 km

 

OP, it will help if you can record a video and share it with us : ) to help you troubleshoot.

 

it’s really
tough to get a video. But i managed to after a few days, here you all go:

 

the revs go up juuuust a tiny bit, when shifting into 4th. It’s really tough to notice, and to hear from the video, but it’s much more noticable IRL

 

Thanks for posting the video OP I can see what you mean, sorry that now I realized I am not able to help since I have the pre-facelift and the programming is different to the facelift I can't say if yours is normal or not, hopefully someone else chimes in. Sorry about that.

 

What did you end up doing with the trans slipping did it ever stop or did u need a new trans ?

 

Your 2017 (according to your public profile) had the same issue? Do you have the latest TCU update? I don't have this issue but I have the latest TCU update.

 

i have the same issue still didnt figure it out yet, mechanics are telling me its fine but im still concerned

 

Did you fix it?

 

Anyway you can be more specific?
This will help you to get the service you need.

MB Specialist can :

1. replace genuine ATF
2. refresh learned shifts adaptations.
3. various firmware tweaks may help
4. Beyond that options are rebuilt jobs

Is your issue specific to "3 to 4th" upshifts banging/slipping with partial throttle somewhat randomly when hot ??

FYI: when you output high-power into a poorly shifted set of clutches, the high friction heats up the thin oil to the point the valve body has a hard time working with.

Take it easy!

 

Yes,

The car in comfort mode from 3rd to 4th increases rpm, about 200. It only happens with light throttle, but quite sporadically. In sport mode it didn't happened. No jerk.
Sometimes I hear a small bang from the front.
The oil in the automatic transmission is new, it was done directly at the MB, a new car battery helped for a month, then it started doing it again. Pump valve is new.

 

what new "pump valve" is that ??

To be practical, if you found that "fresh battery did help" you could try "CTEK Float" to keep your battery in top shape. Chassis performance is directly affected by voltage!

Yes indeed select the "Sport mode" rather than "Comfort mode" around town.

Comfort is best on Hwy to uses a torque converter 2-level clutch that produces heat by unnecessary frictions ... S BEST CITY COURSE.
The S/C option won't "fix 3/4 shifts" issues but help output overall.

 

so i should try adaptation? Or Whats your help, solution

 

Sure, try to retrain shifts adaptations if you are so inclined.
So ppl report excellent results afterwards.

See how long adaptations will last until TCU relearn to match engine throttle.