Originally Posted by superswiss

Not quite. The issue occurred under light to medium braking. The harder, more spirited you slow down the smoother the downshifts actually get. If you slow down spirited it even skips gears like going from 7 straight to 5, and then straight to 3 or maybe even 2. In fact the shift strategy is amazing when driving spirited. This is the first transmission I can drive in automatic mode w/o getting frustrated when I'm expecting a sudden response out of the drivetrain, like suddenly need to accelerate. Also even in Comfort mode it seems to always be in the right gear and ready to accelerate again, as opposed to other automatics that hang out in a high gear and then have to scramble to downshift when you are ready to accelerate again and do it a bit more spirited like out of a turn. It's downshifting very proactively. This does mean that it is less comfortable, though, because there is more engine braking in lower gears. Many other transmission stay in high gears to almost glide when you take the foot off the accelerator, whereas this one quickly starts downshifting the moment you take the foot of the throttle pedal.

The roughness happened when coming to a steady slow stop like a granny stop. For the most part the downshifts are smooth, but that final downshift from 3 to 2 at those slow speeds caused the bucking. Basically, the brief interruption of engine braking during the shift and then the stronger engine braking of the 2nd gear, causes the bucking. Pretty much what happens in a manual transmission if you downshift at very low speeds and let the clutch out too quickly instead of letting it slip to ease in the engine braking. I found the stock brakes in my C63S (the GLC S I believe has different brakes) were not as linear as I wished and somewhat difficult to finely modulate at low speeds. The way I've learned to work around it is to let off the brakes while it downshifts from 3 to 2 and then get back on the brakes. That way the downshift is super smooth. I only have to do that if I creep to a stop essentially. It still occurs a little bit with the new brakes and I apply the same strategy, but the new brakes are more linear and easier to modulate.

Originally Posted by SafeDrive

I had the same jerky transmission issues (even in comfort mode) and sent my 63 to dealer twice for check but there is nothing they can do to fix it. After putting 7000 miles on it, the issue is mysteriously gone. City driving is very smooth. So my guess is the transmission needs at least 5k miles to truly break in.

Originally Posted by kennys2003

are we sure that it's not the driver getting used to the way the transmission works instead of it being mysteriously fixed by break-in ?

Originally Posted by Toughen

The tranny is fine, but I worry about all kinds of noise inside the car, when driving with radio off and windows closed. this is my experience after 2years.

Originally Posted by JonnyO

Either my wife and I have gotten used to our GLC63 or it has gotten used to us. Perhaps it's a little bit of both. The gas pedal can sometimes be a bit touchy for a smooth low-speed launch but not overwhelmingly so- I fully agree with the comments above about some drivers simply not being used to it. The converse of this is that when you intend to put your foot down the vehicle does exactly what you want it to do, with zero delay. To me, that's the way it's supposed to be. The ride is firm, especially on the rutted moon surface that the City of Chicago calls 'a street', but not punishingly so. I suspect some have a preconceived notion of what the ride should feel like before they get in, thinking that an MB star on the front automatically means it should always ride like an S-class.