Thunk when going into S, S+ or manual
 

Hey all,

I always switch into the S modes or manual at a full stop with the transmission in gear. I always get this sort of mild lurch but not unusual sounds. The trans shifts fine in all modes though. Anyone else experience this or might there be an issue I need to have checked out? As always, thanks for your replies and insights.

A lurch like if you were to slowly creep off the brake and then get back on it?

It's the car shifting into first gear because C starts in 2nd.

yes, this! although my 2009 had a more pronounced lurch than my 2013.

This

Hey guys, just want to confirm that the "lurching" going from second into first while stopped in gear is okay on the transmission. Should I shift into neutral at a stop before changing from comfort to sport/sport +/M? Every time that lurch hits, I cringe!

Normal

Mine is 2013 sedan and I can start it in 2nd by putting it there but otherwise it starts in first.

Had the same issue. Took it in and got new trans software all is good now. Was covered under warranty, so if you still have coverage you'll be all set.

What are you talking about? C starts in 2 unless you paddle down. S, S+ and M always start in 1. If you are looking at D2 at the bottom of your display, that's not the gear you are in. Are you looking at the ///AMG display? That shows you the actual gear the car is in.

Sorry mate but mine does not start in 2nd. I have been around MB cars for nearly 30 yr and it struck me as odd so I checked and it is starting in 1st. Not hard to figure. Just count shifts.
Normally I would agree with you but not in this instance.

GO. TO. THE. AMG. DISPLAY! You are flat out wrong. C mode starts in second. Period. End of discussion. Not even the TCU tuning lets you start in other gears. Like I mentioned, the only way to get the car to start in 1 in C is to pull the left paddle. And there is no way to start in 2 in other modes.

yup. Just tested it to make sure. C starts in second for me.

Well let's see here. Foot on brake, trans in C, release brake, depress accelerator and count. 1, 2, 3, 4, 5, 6. 6+1 =7.
Now we all know there is theory and then there is practise. We also know there are exceptions to the rules.
We also know that a computer controlled system never screws up right?
None of us has had a PC or a Mac freeze up or crash.
We have never had a rotary dial on an appilance fail right?
We also know that the selector switch under the knob is failure proof as well eh?
I concede that the car is supposed to start in 2nd when in C. Even the earliest W124s I had started in 2nd when the W selection was made on the console.
My particular car does not start in 2nd when in C which suggests to me there could be a problem that I will get my guy to check next time I in.

Are you looking at the display? Seriously. Not being a jerk. I'm asking for real. The MCT isn't the smoothest box out there and sometimes slips itself and whatnot. What you may PERCEIVE as a shift may not actually be a shift. Unless you are looking at the AMG display and watching the car shift itself, I'd still say you are wrong. So I'm saying, prove it.

First of all why do you have no space to accept that maybe something is not right with my car which I have only had 5 weeks?
Second, I have driven cars from MB since 1987 exclusively with 4 spd, 5 spd and 7 speed trans so I think I can determine what is happening. I don't need the AMG screen. I have this odd instrument in front of me called a tachometer. You have seen one of those right.
When it shifts, in case you forgot, the revs drop. That is all I need to see.
I am off this for now. I will come back to it once I get the car checked.

Are you talking about the thunk between C to S/S+/M, or the guy saying his car starts in 1st?

Display shows 2 at a full stop in C. Why would it show 2 if it was really in 1?

I can tell the difference when starting in S/S+ vs C.

I don't count too well but my ass knows when a shift has occurred.

TC

ETA: c63AMGee--The thunk is what sometimes happens when you change modes from C to S/S+/M at a stop. The hijack came when someone (correctly) stated the S and M (tee hee...) modes put the tranny in first gear to start from a complete stop vs the tranny being in second gear for standing starts in C. Someone objected and now, we're off on this tangent.

Haha thanks man. I was following. End of day, just want to make sure the downshift from 2 to 1 when switching modes in gear (drive) isn't putting undue stress on the transmission (vs. switching modes in N). Sounds like it's fine. Completely agree the car is clearly in 2nd gear in C mode.

You must have one of those special DTM transmissions

Seriously. What does the display say? Because that's going to be correct. Maybe you can count along with the numbers and come back. Are you saying that on your car, the C-mode version of driving in 1st perfectly matches with the 1st gear experience in the other modes? But the display says what?

:bow:

Mine definitely starts in 2nd when in Comfort.
If you are standing still, and you switch to S, S+ or M, the car shifts to 1st, and you get a slight thud as it shifts.

It has a multiplate wet clutch. When that clutch locks up, maybe the revs drop making you "feel" a shift when in actuality it is still in 2nd and had been from the start? Why can you not accept that the car starts in 2nd? You refuse the look at the display. Fine. Don't believe me. You've had the car for 5 weeks. You must know everything about it.

Mate, it starts in 2nd. We've known this since it came out. Please. It takes more work to type up what you think you felt rather than switching to the AMG menu.

Car will always start in 2nd gear if in comfort mode. The thud you experience is just working as intended. I always leave the AMG display on my car when I start it up, and when moving between drive modes (comfort to sport) the car will shift from second to first.

Side note I think you can put the car on standby, select the drive mode sport, sport +, manual and I believe when you start the car up it'll start in first gear. as it will not be in comfort mode. Don't quote me on that though i'll test it next time I get to my car, or you can it won't damage your car.