My vehicle has just turned 1 years old and I had brought it to the dealer for its first service. I mentioned to them that at times, the driver's side window switch does the opposite of what it's suppose to do (goes down when it should go up). Then I mentioned that at times, it jerks a bit when it is downshifting. They told me that they would have to keep the vehicle for a few days and flush out the fluids in it to reset it. I brought it in last Thursday and they told me that they have opened a claim with Mercedes Benz about it and the foreman is working with them to resolve this issue. I hope this isn't a bigger problem at hand, although they didn't seem to worried about it. Has anyone else come into this issue? Overall, the vehicle runs great, just jerks a bit when downshifting at lower speeds. TIA (P.S. I never had any lights displayed on the odometer for this issue)

 

I wonder if it has to do with auto start/stop, X254 has a mild hybrid system (48V), try disabling auto start/stop and see if it helps.

 

I have a 2016 GLC 4Matic that I purchased in 2019 as a CPO from the dealer. It does that on occasion. Not all the time, and I haven't figured out the trigger, but it only happens when braking to a stop. I have never had any other issues with the transmission. I normally disable the Start/Stop feature when I drive, so that is not the cause. My car has approximately 45k miles on it.

 

7.22.2024

In this thread New 2024 GLC300 At Dealer 3 Days for Annoyances - MBWorld.org Forums I explain how Mercedes fixed my jerky downshifting earlier this year. The transmission had to be "retrained".

Good luck!

-Allen

 

Did you notice a drop in fuel economy after this "fix"?

 

I really didn't notice one way or the other, because at that time the car didn't have 1,500 miles on it. I had no experience with fuel economy of the vehicle. What I've found that's strange regarding FUEL is how it holds more gas if I fill up with the engine running, than with the engine off. Gonna start a thread on this subject in a few days.

 

I had this issue and my dealer told me there was a recall on this and updated the software on a module and after seems much better.

 

This is an interesting post. We have had the same problem with our 2024 GLC300 since day one. It doesn't happen every downshift, but at least two or three times a day. Googled some reviews and people said that MB's transmissions all have this jerking problem, form the A series to S series. So, kind of get used to the shaking when press the brake. But, once I read this post, it sounds like there is a solution. Does anyone know the procedure to "retrain" the transmission?

 

It is called stand still adaptation

 

Can't find this feature in the manual. Is this a function only the dealer can do? Any more detail on how to apply it?

 

The dealer did it for me. Took TWO VISITS one week apart. My 2024 GLC300 had less than 500 miles on it at the time. The technician drove the car hot/cold gathered data. He transmitted that data to Mercedes HQ (wherever that is). A few days later called to say bring the car in again, and leave it overnight. He drove it about 25 miles under various conditions, 3 times over a 2 day period, applying whatever "fixes" Mercedes told him to try.

The car now has 5,100 miles on it and coasts/shifts perfectly...about 99% of the time. (But I'll never buy black again, lol.)