I have 11K miles on my GT63. After I broke the car in, I started to feel that whenever I go into 4th gear I could feel the shift A LOT harder than the rest (on Sport + and Race Mode). I am feeling it a lot more now but when I down shift from 5th to 4th. Is only on 4th gear that I could feel this. Is this a problem? or is it normal on this vehicles. I was told that it might be because that is how the transmission is made and also because that is the gear with the highest TQ. Anybody that could help with some feed back or if anybody had ever had this issue?

 

What year is your car? I have a similar problem with an 2016 CLS AMG 63 S, only in sport + mode hard downshift from 4-3..and a lazy upshift from 4-5. Intermittent problem and only in sport +, never did it when the car was newer. I had the dealership upload a software update and reset everything and it was fine for a while, then started acting up again. Seems to be software related, but moving on from that car…. Sad to hear it exists in the new model!

 

As opposed to the 2016 CLS 63, the GT 63 uses the new 9-speed MCT, not the old 7-speed, so they are not comparable. They are internally quite different. There is a level of shall I say feedback from the MCT, because it uses a wet clutch instead of a torque converter, so it feels much more like a manual transmission or a sporty dual clutch and it's super responsive to throttle input. It does take some judicious throttle modulation to shift smoothly. That's normal. In S+ at least in my 2019 C63S it deliberately gives a kick in the back when shifting under load. Not so much in Race to avoid upsetting the chassis on the track. I do love the fact that this transmission isn't numb like your typical automatic transmission, but on the other hand if you expected Buick like shifting, then you are driving the wrong car.

Having said that, though, I don't have unusual harsh or clunky shifts and I have driven several GT 63 as well, including the new E Performance in Germany, and haven't experienced anything like this. As I said, the transmission is overall more aggressive, direct and lets you know that it shifted, but it's all part of the experience. The one thing I'd add is that I never drive in automatic mode outside of C. In S+ and Race I'm always in manual mode choosing my own gears. I have a long standing theory that the TCU doesn't really know how you wanna drive if you mix moderate and sporty driving in the automatic mode, or use S+/Race around town instead of reserving those modes for actual sporty driving. So in case of my car, the TCU only had to adapt to my moderate around town driving in C. Any other type of driving I do in manual mode, so the TCU didn't have to learn my sporty driving style and come up with a compromised adaptation that covers moderate and sporty driving.

I particularly noticed that this strategy is working after my European Delivery trip. I did a lot of high speed German Autobahn driving for 2 months after taking delivery of the car and as a result it drove rather rough around town. Shifting in a jerky manner and particularly insisting on downshifting to 1st gear before coming to a stop, which made every traffic light stop rather jerky. After a while, though, it noticeably adapted to the increased around town driving I do here, and most noticeably it suddenly stopped downshifting to 1st gear when coming to a stop. Since then it only downshifts to 2nd gear and only goes to 1st once I have come to a complete stop. So the shift behavior and quality is largely subject to how you trained it. If you confuse it a lot with different driving styles, it doesn't really know how to adapt.

 

Is a 2021 GT63S. I have been told that the transmission is built to do that but idk.

 

Thanks for the Input. It makes sense. I actually have heard that a lot. That this cars are made to learn your driving habits. This is my first AMG and i did not know if it was normal. I drive it HARD but when I drive it around town, I do drive it normal (I drive it hard 80% of the time). I could only feel that in Sport +. Also another thing that i noticed is that it does it more when it goes into 5th and I quickly down shift to 4th. If i give it a few seconds it only does it sometimes. Other people have told me that it might be because 4th gear is where it has more power and TQ but i honestly dont know. I was just wondering if my Transmission is going out or if its normal. It is modified aswell. ECU, TCU, CPC and DP

 

I am having the problem like you said, coming to a full stop then the transmission jerks, I tested out another GT63S that doesn't have the same problem as mine, I am wondering if I should take it back to the dealer or leave it as is, the dealer just replaced the rear diff according to the rattle noise

 

I have the exact same issue in my 2019 GT63. When off throttle and slowing down the shift back to 4th sounds very "mechanical" and unpleasant. I'm always in "individual" but I'm pretty sure I have that set like Sport but the suspension is comfy... But it will do it in comfort as well.

 

Everything was fine until today. 40 min into my normal commute I got the message that my transmission was overheating. The message instructed me to pull over keep engine running so it could cool down. This is my second drive since picking up the car from the dealer for a faulty fuel pump…. Wtf, this is getting concerning.

 

The cause of high transmission temperature or overheating is often the result of a pierced radiator. What year is your car? The radiators used to be exposed and a rock at high speed could easily punch a hole. As of 2019, AMG now installs guards on all models from the factory like shown below. If you don't have a black mesh over your radiators, then it's likely that you have a hole in the transmission radiator. Perhaps coincidently after you picked up the car, or it was already there and finally the fluid got low enough to overheat the transmission. I believe there's a service bulletin to retrofit the guards, too.

 

Update- the car has been at the dealer since my last post. They have separated the engine from the transmission 3x to replace a seal.. failed 3 times. Still leaks. Now they are thinking crankshaft.. if that fails they will replace the engine. Meanwhile I have no loaner car and I can’t seem to get mbusa to return my calls. I am rather disappointed in the customer service and inability to repair the car in a reasonable timeframe.

 

Update- the car has been at the dealer since my last post. They have separated the engine from the transmission 3x to replace a seal.. failed 3 times. Still leaks. Now they are thinking crankshaft.. if that fails they will replace the engine. Meanwhile I have no loaner car and I can’t seem to get mbusa to return my calls. I am rather disappointed in the customer service and inability to repair the car in a reasonable timeframe.

 

Man that sucks. Is your car past the point they would do a buy back? I assume it is - but that many problems sure does suck to have to live through especially with no loaner or anything else.

 

Lemon law it for sure, and MB not giving you a loaner on one of their ‘halo’ cars is scandalous!!

 

They returned the car to me yesterday. Did not make it home before the check engine light went on. I don’t know what to do with this thing. And they did not give me any paperwork when I picked it up. You can’t make this **** up…