My 2020 GLC 63 AMG has about 4000 miles. I have been waiting for it to behave properly when driven in a normal (non-race) manner but it remains really impossible to drive it smoothly from a start all the time. The shift from 1 to 2 gear sometimes is fine but often it lurches, jerks and is just plain unacceptable for an $86 thousand dollar car.

My question to all. I am sure this transmission is controlled by a computer. Does anyone know if the dealer has the ability to modify it's behavior vis software?

 

You may have the wrong expectations. As you may or may not know, the 63 AMG models don't have torque converters. Instead they have a computer controlled wet clutch specifically to make the car feel more connected and more responsive. This does mean that you will feel a lot more of the jolts and jerks in the drivetrain that are otherwise absorbed by the oil in a traditional torque converter. This is intentional and one reason I own an AMG. Many other performance cars have gone with torque converters that IMO just kill the connected feel and responsiveness of a proper performance car. The AMG MCT transmission offers more of a feel similar to a manual transmission. To be perfectly honest, these cars are not a 100% at home being driven slowly in the daily sludge. They are much more at home on the open road, where you can drive them assertive and dynamic.

You can reset the adaptations. What this does is clear everything it has learned from your driving style so far, and start adapting fresh to your driving style. This could potentially smooth some things out if it learned a bad habit from you, but the adaptations continuously evolve over time anyway. I did European Delivery with my C63S and over there I mostly drove on the Autobahn and very little around town and cities. Once the car got here it was quite jerky around town, but over time it adapted and learned to shift more smoothly around town. For example at first it always downshifted to 1st when coming to a stop, which was rather jerky, but after a while it learned to stay in 2nd gear until the car came to a full stop for a moment before going into first. Which also means that we brief stops it never goes into first and I resume in 2nd. This is also possible in manual mode now. I can hold it in 2nd and start off unless I came to a full stop for more than a fraction of a second. Honestly for me it really only started to feel right around 8-10k miles, largely because I drove the first 6-7k miles in Europe. I also learned to properly modulate the throttle to control the shift points or use manual mode to override it when desired. For the sluggish stop&go traffic I have the full driver assistance features and DISTRONIC does a pretty good job driving the car smoothly when things are sluggish. At times smoother than I can do myself.

One thing I've learned is that if you are hesitating from a stop, it gets somewhat jerky. I often let the car ahead of me go, so I can start w/o easing off the throttle before it shifts into second if the car ahead doesn't quite get out of the way fast enough. Any easing up on the throttle tends to lead to a jerkier 1-2 shift. You kinda have to let the clutch grab fully, otherwise it has to quickly disengage the clutch again and that gets jerky as it does in a car with a manual transmission. Having driven manual transmissions for almost 20 years has provided me with the sense and muscle memory to feel what the clutch is doing.

I do think the dynamic engine mounts in the S models make a difference, too, because the drivetrain is not mounted as stiff to the chassis when driving casually. I say this because there is a service campaign for the AMG Drive Unit. They had a bug where the dynamic engine mounts didn't work correctly due to a coding error. The transmission in my C63S has gotten smoother since the update when driving casually, so I suspect the engine mounts weren't as soft as they were supposed to be for normal driving before the update. The dynamic engine mounts basically solve the conundrum of isolating the chassis and body from the drivetrain jolts and vibrations during casual driving, while also stiffening the mounts during dynamic cornering so the engine and drivetrain move with the chassis instead of lagging behind.

 

How do you reset it? Have tried disconnecting the battery in my 2020 63. Didn't help.

When I first picked it up, it was 100x more responsive. Buy of course over time it adjusts to traffic jams.

 

I don't know what the current procedure is. It has changed over the years as far as I know, and it's possible with the current models it needs to be reset via Star Diagnostics, so you'll have to take it in to the dealership. It will definitely adapt to driving style. I've even noticed short time adaptions. When I come back from the canyons, it drives more aggressive even in Comfort mode, until I drive it at normal pace again for a while. Haven't felt a reset is necessary.

I do however recommend you don't mix drive modes for various duties. Don't drive around town in S+ some times and then aggressive in S+ other times. That seems to confuse it as to how it thinks you typically drive in S+. At the AMG Driving Academy our instructor specifically talked about using the correct mode for each driving situation. Use Comfort for normal daily around town driving, and on the highway you can put it in S or S+ or whatever you want. I generally use C with transmission in Automatic around town, in traffic or on long highway journeys with DISTRONIC and Active Steering Assist engaged. For daily short distance somewhat spirited highway driving and open road driving I put it in I*, which I have setup like S+, except the suspension in S and the transmission in M. Then in the canyons I used to keep it in S+ with transmission in M and ESC in Sport, but have recently changed to putting it in Race with transmission in M and ESP in Sport, but the point is I have distinctly different driving styles in each of those modes.

 

Is resetting the only mod a dealer can make? In my mind the solution to this would be to adopt the way the 43 works and start out in 2nd gear in comfort mode.

 

This transmission does not do comfort mode. There is an aftermarket tune for around $2K but i am not sure how much does it help. You should ask the tuners like Eurocharged. For me S is the smoothest of them all. I do agree staring in 2nd might help with this issue.

 

I am soooo far over my pay grade here, but...
This link is for the 7 sp tranny. No idea if it works for others. This worked for me. My '14 GL450 CPO shifted like crap. Dealer said nothing wrong. I followed this procedure and the staying in gear too long went away. I did exactly what the procedure called for. After clearing the shift points I drove around with the lightest pedal I could. That did it.

http://www.mercedesmedic.com/reset-m...-instructions/

 

Has anybody tried the reset transmission instructions to see if they work on GLC63S?

 

Yes, it's the only modification they can do short of software updates from the factory. The old 7MCT starts in 2nd gear and the 43 used to start in 2nd gear in comfort mode, but AMG changed that starting in 2019 and specifically the 9MCT always started in 1st. All FL and new AMGs now start in 1st gear in every mode. They did this for a better response in every mode. I never liked the 2nd gear start of the 7MCT. Felt weird and even though the engine has plenty of torque it felt like it was lugging it and starting off in comfort mode was lethargic. You can try using the new Slippery mode, which reduces engine torque and smoothens the shifts. It's mainly meant for driving on slippery surfaces as the name implies and make it less likely for the wheels to suddenly lose traction, but the softer off the line start in Slippery mode might be what you are looking for. One of the characteristics of comfort mode is that in the name of fuel efficiency it upshifts quite early, so the 1-2, and 2-3 shift happens while the car is barley moving. Interestingly the manual mode doesn't allow shifting that early. So one way to smoothen it out is to use manual mode and stay in 1st gear longer. I sometimes do that.

 

It is just responsive. As a long time race car driver, mine seldom ever does this. When I drive my foot is properly on the throttle and applying proper pressure so I can take off slow and controlled in normal situations. Now if I just get in and try to drive it like a torque converter car, it will buck.

Learn to properly drive a dynamic car in an aggressive setting or leave it in comfort. You could use "Individual" setting, set the drive train to Comfort and let everything else be aggressive and see how you like that.

 

Wow great explanation. I brought mine into the dealer a few times for this and was never told this.