My salesman where I bought the GLC 43 just emailed me that a 2025 GLC 300 C4 is coming to the dealership with all the options see attachment to trade with my 43 AMG, of cource I will test drive knowing what to look for. Any inout about the GLC 300? are there any issues in that vehicle that I should be looking for? Thanks

 

I have the same issue. I purchased a brand-new GLC 200 in December 2024, and at 1,200 miles, the vehicle started experiencing transmission problems. It jerks noticeably when shifting up or down, creating an unsettling “jumping” sensation. I took it to the dealer, where they performed software updates and reset the transmission parameters to factory settings, but the issue still persists. Has anyone successfully resolved this problem? I would greatly appreciate any suggestions on how to fix this defect.

 

Looks like we have to live with it ...it's just the way this transmission is developed as a manual trying to play the automatic part.
Terribly disappointing

 

Really disappointed with the brand. What surprises me the most is that this issue doesn’t affect all vehicles—it only occurs in certain cases. I know people who own a 2024 GLC 200 and have never experienced this problem. I should have bought the BMW X4 instead. 😞

 

Hindsight and I should have waited for the new SQ5

 

I guess don't give up yet, try asking for a specific adaptation, called "stand still" adaptation. It has to be specific, it takes time and it takes a couple of tries to get it right. If your dealership isn't willing to help, try different MB dealerships.

 

The adaptation might not solve the issue but it will mitigate it.

 

I had the same issue and took it in a month after purchasing requesting the transmission and braking be checked. At the time they informed me that I had all the updates and I purchased a performance vehicle whereby this is expected behavior.

Last week I took my 2024 GLC 43 in for service as the 1-2 shifting got real bad both upshifting and downshifting. It always seemed to stumble thru the first gears when softly accelerating (light pedal) which is why I took it in originally but the transmission started hard shifting 1st to 2nd gear even without much acceleration and when stopping would harshly downshift. MB service informed me of a new SW update that addresses the jerky shifting when I dropped it off.

They found fault code LI27.60-P-079083 whereby they rinsed the valves to resolve.

They performed the SW update informing me that they applied SCN coding of N179/1 and software flash of N62/4. This made a significant difference eliminating the stumbling/jerky (that the vehicle always had since new) and the braking is much better addressing the over sensitivity/lack of modulation.

The vehicle now drives up to par with the badge it wears, it is a completely different vehicle now. I was on the verge of trading it in but given that this resolved all the concerns I am keeping it as it drives great and has the performance edge which is why I purchased it in the first place..

I never post anything, but am now so folks are aware of the update given the significant improvement it makes. Hopefully this is helpful.

 

Thank you TonyTV, I will definately contact my service advisor, just curios if your GLC 43 is AMG or not? I honestly do not think it makes any difference between 2024 and 2025, According to AI for brakes and transmission it should be the same.

 

It is indeed a 2024 AMG GLC 43.

 

is there such an animal that is a GLC43 and not an amg?

 

I did speak to my service advisor and he confirmed the update you mentioned is available so will get it updated, as far as the brakes did your breaking improve after the software as well? I absolutely despise how these brakes lock up, very dangerous and every time it happens I feel like I could get a whiplash.

 

It improved the braking as well. Before the brakes had no modulation to guage foot pressure when coming to a slow stop resulting in having to back off foot pressure with no feedback whereby the over sensitivity of the brakes often resulted in harsh stops. Now when I brake it’s more gradual than abrupt with some feedback more like a normal vehicle brakes.. I dont know if its resolution was part of the SW update, they did not mention doing any other work aside from the valve flushing and stationary adaptations (WTHeck is stationary adaptation….). Note that I had brought in the AMG due to VERY harsh shifts from a start and VERY harsh downshifts when braking so much that it was jerking the car real bad.The following is what they send to me so you have all the information possible. Note that the guage cluster was reporting Active Emergency Stop Inactive which they also resolved (was intermittent).

“Good morning. The vehicle is heading to wash and will be ready for pickup in about 20 minutes.For the drivability concern, we test drove the vehicle and confirmed the complaint. We connected diagnostics and a battery charger, then performed a short test and found fault code LI27.60-P-079083. We followed the work instructions, confirmed proper fluid level, performed valve rinsing procedures, and completed stationary adaptations.Regarding the error message on the cluster, we performed a short test and found fault U186B29 and LI46.10-P-078012. We completed the outlined work, including SCN coding of N179/1 and software flash of N62/4. All faults have been cleared from memory.”

 

Ok thanks I guess I will see what happens. Hopefully I will see noticeable improvements.

 

Thanks all for the feedback, I am in the same boat now too with my better half's brand new 2025 GLC43.
The transmission is completely unpredictable. One day it's smooth as butter, the other day it kicks and lunges.
I feel like it would stall at times, even in Comfort. Especially going uphill and stopping uphill.
Today it jolted big time upshifting from 2 to 3, legit scared me a bit. Car has less than 500 miles on.
I'm giving it a few more weeks but will already reach out to the dealership giving them a heads-up.
I have a 53 and am not a stranger to weird MB shifts, but this is something else. Otherwise love the car.

 

Make sure they have done the update TonyTv suggested mine is getting done tomorrow, how is your brakes? Do they lock and push you forward like you just hit somebody?

 

Yes will do... no brake issues thankfully but I do have a very creaky main screen assembly that also needs to be looked at

 

7/31/25
Update on my saga with this car. Rough transmission continues to act up. The car is completely unpredictable. It is currently at the dealership where they are performing another "software update" as well as another standing adaptation. The car was there on 7/15 where the same thing was done and the problem was not solved. This brings my total days out of this car to 26 and climbing.

At this point i had no choice but to open a lemon law case with Mercedes. I am hoping for a full buy back. Does any one have any tips on the process itself? Has anyone experienced a buy back from Mercedes?

 

We still have transmission issues as well even after the updated software, frankly I am tired to deal with it any longer, tired of going back and forth to the dealership so we have decided to just put up with it.

 

I think it really is just the way it is. It grips the gears hard because its supposed to. I understand peoples concerns, but if your pedal inputs are just a little more than having grandma foot then you're fine. Buying a twin turbo means it's meant to go fast. It just grips the gears aggressively. That better than it slipping when it switches gears in my opinion.

 

Car was dropped off at the dealership on 7/15/25 and stayed there until 8/19/25. During this time they replaced: the valve body, and the electro-hydraulic control unit. This essentially equates to replacing the majority of my transmission. During the time the car was in service I opened a Lemon Law case with mercedes. Took them about 3 weeks to run through their procedures and gave me an approval this week. Now waiting for Sedgwick to contact me to finalize the details. This has been a process for sure but happy that mercedes is sticking by their product. IF anyone has questions or needs guidance on lemon law process with mercedes, im happy to help.

 

All the best with the lemon law process, what will you get next?

 

Purchased a 2025 Mercedes E450 All Terrain

 

not a bad choice : )

 

Maybe after a while you will understand. I realized I was throttling like you do. It isn't a driver issue, your car has the same issue. Mine became too dangerous. I had bog down when turning left....cars had to stop. I did a uturn and hit the gas...cars were coming. Catostophic transmission failure message...engine shut down...had to stop and put in park to restart. My car has been with Mercedes for a few weeks. I won't take it back until it is fixed.