New 2019 Coupe Jerking/Bucking Issue
 

Just got my 2019 Coupe a week ago. There was 10 some miles on it, not a big deal. But the car has been jerking at low speed since day one. You can feel the shifting especially under 5 between gears and not smooth at all. This is definitely not something I expected from a new vehicle, let alone an AMG branded one. Has anyone ever encountered the same issue and is this normal in the break-in stage as what the dealer told me? Thanks for any input!

break it in a bit - it will 1. learn your driving style and 2. the transmission actually needs to break in

if you're still having issues after that - post again/ bring to dealer

And what mode is this happening in? Comfort or Sport+?

Everyone will imply that's normal for c43. Do I like it no. Did I learn to live with it, yep.

Your car should jerk and buckle like mad bull in S+. In comfort, it does every now and then while slowing down on 2nd gear, just remove your foot from the brake should ease the jerking. The engine braking is terrible on this car, uses zero torque converter which is retarded.

I usually drive it in Comfort mode but I have tested it and it happens on all modes when accelerating from a stop or slowing down to 1st or 2nd gear. It doesn’t make much sense to design it in a way like that. I’m now really worried if my girlfriend is putting on her makeup or drinking water beside me...

You never tested the car??

You’ve described it well, mine behaves the same way.

I did and that’s what the dealer told me. Break in and learning. I just can’t believe it’s not even as smooth as my Honda...

I just found there is a feature called Transmission Reset/Relearn. I’m probably going to give it a shot before I take it to dealer.

I don't mind the jerking so much as it's expected, however sometimes i wished they would employ the same tech as when you're in manual Sport + mode. You can stop in 2nd gear and it'll shift back to 1st when in a complete stop. Prevents any jerking compared to auto in Sport +. Not a big deal but a nice to have.

Just brought it in and had a dealer inspector ride with it. He said all I'm experiencing is completely as designed...since a lot of customers have asked for it to feel like that. Totally don't get it...

Do you have a coupe or sedan? How is it in Comfort mode for you?

Here's a tip: You have to be very smooth with your throttle input when in 1st gear when you're in S+. Because the transmission software is set up to be super responsive and aggressive, particularly in S+, it does not like indecisiveness.

Any oscillation of your foot, hesitation/indecision (pressing the accelerator pedal a little bit then backing off) will result in this behavior. If you're gently pressing the throttle and go over a hump in the road that causes your foot to dip into/back out of the throttle, you will get this behavior.

You can still drive at low speeds in S+ without experiencing this behavior, you just have to learn to "roll on" the throttle, instead of stabbing it with your foot. If you need to go to the brake, then decisively remove your foot from the throttle, rather than easing off of it.

The BMW M DCT (dual-clutch transmission) behaves the exact same way at low speeds. It was present in every M-DCT equipped E9X and F8X M3 I've ever driven.

Using this approach, I've only experienced 1 "rodeo ride" and that was down to user error on my end because of jerky throttle inputs on my end. Hope that helps.

There's an entire lengthy thread on this subject if you search. I can't give you a perspective for the C43. I have a '19 C63S, which has a slightly different transmission. It's the same 9 speed at the core, but instead of a torque converter it has a startup clutch, similar to dual clutch transmissions. The transmission is programmed rather aggressively which seems to be the case for the C43 as well. These are performance oriented cars, so it's desired or expected to some extent. However, the transmission learns how you drive and adjusts. My C63 was quite jerky at first, but learned my driving style. At first for example it shifted down to 1st gear when coming to stop, but after I while it learned to not shift lower than 2nd until the car comes to a full stop for a couple of seconds. This transmission is also capable of skipping gears. At least in my C63 in C from a stop with casual acceleration it shifts 1-3-5 in fairly short order, skipping 2 and 4. It does it almost too quickly so it's not always as smooth. Can be overwritten by shifting manually, or put it in S. If I give it a bit more assertive throttle it holds the gears longer from a stop and doesn't skip gears, making it smoother. It's a learning process. You have to learn how the car behaves and the car has to learn how you drive. It gets better over time. The transmission reset at this point is pointless, because your car is already in the initial learning phase. It is possible for the transmission to learn bad habits depending on how you drive. For example I recommend to avoid stop&go traffic during the break in period. That's not a good situation for the transmission to learn how you drive. The transmission reset is something to do down the road if you find it still shifts crappy, so you can start over with teaching it how you drive.

As for your girlfriend, tell her your car is not a powder room nor a dining hall ;)

Thanks for the tips. It’s very helpful in S+ mode.

You are right on man. Do you still remember how long Its taken to get the shifting smoother? Sounds like I shall drive more aggressively?

As far as I recall, it started to feel right after a few thousand miles and me driving in different modes in different situations. I also get the impression that it learns short term from how I drove recently. For example entering a town and suddenly driving at lower speeds after an extended high speed aggressive German Autobahn stint was met with rougher shifts even in comfort mode around town, whereas if the car had sat for a bit and I started to drive off in town it drove smoother. I also have the driver assistance package, and I frequently used the adaptive cruise control to just let if follow the traffic in town. This one works really well, coming to a smooth stop and then resuming when the traffic starts going again. It actually takes off much smoother than I was capable off, so it's definitely a matter of how one modulates the throttle. I still have to further train my muscle memory and I'm sure the car has to learn more, especially since my driving style will change once I get reunited with it and start driving it on US roads. The first 2 months and roughly ~6200 miles were all done in Europe. I just got back Sunday night and the vessel with my car on it left the port today. Supposed to arrive at the west coast on Aug 7, so with customs etc. it'll probably be mid to end of August before I get to drive it again.

A few thousand miles is quite a bit of time for the learning curve. Wish I had chosen the driving assistance package instead of the parking assistance package. Welcome back and good tips for my gf btw. Lol.

My pleasure! The other thing you can do to immediately bail out of the situation is grab a shift by pulling up on the right paddle.

Definitely understand where your concern was coming from, particularly if you had never encountered this behavior before. I first experienced when test driving a DCT-equipped E90 M3 several years ago.

Also experienced it on my C43 test drive. Once I discovered that the transmission behaved similarly to the M-DCT in S+, I just treated it as such. I've never experienced any of the bucking when in C or S.

The one thing I wish it would do that my Porsche does is start in 2nd gear for comfort mode. My Porsche starts in 2nd gear for comfort mode, but 1st gear for Sport Mode. It makes it so much smoother when not driving aggressively.

I thought the '19 C43 still starts in 2nd in C. That's what the old 7 speed transmission used to do, but with the 9 speed you can just put it in Slippery mode, or put the drivetrain to Reduced in I* and it should start in 2nd gear.

My '18 starts in 2nd when in C, last time I was paying attention.

Easier solution is to get a new girlfriend.

Secondly, your car is dropping to 1st gear in comfort? Can you make a video of this and share here? Cause that is not normal.

That’s not as easy a solution as it sounds, haha.
It only drops to 1st gear when it comes to a complete stop and then restarts in 1st gear in Comfort mode. Is that normal? If not, I’ll do a video tomorrow.

I have a sedan. In comfort mode it's smooth and you don't notice the shifts at all.