ET_Skipper

I bought a brand new 2009 C350 in Nov. Now has 8k miles on it.

When I start the car, when the engine is cold, the transmission jerks from 1st to 2nd gear shift (Both in C and S modes). Only happens when the engine is cold at the first start. Is this normal?

jamaicakevkev

don't know if this is normal but know I dislike this 7 speed transmission big time... seems like trouble coming down the road don't plan on keeping mine 2 long

ET_Skipper

Do you get that jerk too?

RLE

Why are you not asking this question at your dealer?

Of course it isn't normal. And BTW, I love the 7speed. Vastly better than the old 5 speeder in my W203.

Nevada Jack

The 7 speed tranny is probably the most successful transmission MB has produced. I have had it on 4 different models and with the 5.5 liter engine is a match made in heaven. I have had my C now for a month or so and have a 1000 miles on it. The transmission is getting closer to perfection as it adapts to my driving style. If you have some jerking between 1 and 2nd then get your dealer to flash the software and if that doens't fix it, persist until they eliminate it.

This transmission is going nowhere so best get used to it.

jamaicakevkev

Not bashing the transmission just saying that I am uncomfortable with it. when switching from D to R or vise versa there is this weird delay and even when I drove it today with 1900 miles on the clock it just didn't inspire confidence that this will be a long lasting trouble free transmission.... It gave me the same uneasy feeling just like when I first drove this car home from my dealer 5 months ago. Having driven Hondas toyotas and lexus hey even my chevy Avalanches I truly dislike this transmission I always believe simpler is better and think this thing is just overly complicated. Since my car was brought down here gray market, I have to be concerned about the life of my transmission since I probably have no warranty.

I feel a little better after reading your post and truly hope for my sake that this will be a trouble free transmission.

jamaicakevkev

NO jerk from 1st to 2nd ... but I get what feels subtle but still weird gear selections and an awkward delay when switching direction from like R to D.

ET_Skipper

When you say "flash the software" do you mean reset the software? If that does not work what else can be done? Thanks a million

Nevada Jack

Early models of this tranny had problems with jerky 1st to 2nd changes, especially on coming to a stop. Most of these problems have been eliminated and I think your dealer should be able to deal with it.

It really is a fine transmission but as with anything MB makes, driving with no warranty can be a costly adventure...:-)

Nevada Jack

Yes... they reset the transmission software. If the problem persists, then the dealer should diagnose the problem and find out why.

You may also do a search and find out how to reset the ECU (?) by pressing the accelerator to the floor with the key in position 2 for a period of time and then shutting it off. It basically sets the default of the transmission shifting so that you start fresh on the "adaptive" features which is based on your driving patterns.

ET_Skipper

Thanks, do you recommend I reset the ECU and see if it helps before taking the car to the dealer? I know the dealer will say "we could not replicate the problem" because when I take the car to them the engine will not be cold and it won't jerk between 1st and 2nd?

joshg1001

i dont get it on 1st to 2nd, but when im going up a hill, and it decides to shift down, the car does lurch while its shifting down. its not as smooth as it can be

atspring

The only way I can feel a shift is if I force a down shift with the shift lever. Mine is an incredibly smooth tranny.

There are two possible issues. First, driving stle may have "trained" hard downshifts in to the ECU. Try resetting the ECU, then try driving smoothly. If you still get hard shifts it is time to see the dealer.

Work with the dealer. If it only shifts hard when cold, plan on leaving your car overnight. Meat the dealer in the morning, take them for a drive and demonstrate the problem for them.

axhoaxho

My wife also has a 2009 C350 Sport. She drives the car every morning since last Winter, and the car has no transmission-jerk at all. I also drive the C350 from time to time, and I didn't feel any transmission-jerk ever as well.

Regards,

mat2hu

do you mean in Tip??? my transmission jerks as well only when the engine is cold or when i go from second gear to first gear and the car isn't at a full stop but it still downshifts... i kinda like it actually but it goes away after like 5 min when the engine heats up or if i shift when the car is at a standstill i feel a little jerk as well when i shift from 1st to 2nd or vise versa; it lets me know that my car is actually changing gears and i like it.

Nevada Jack

It is worth a shot to see if it solves the problem.

The cold engine thing may be that the idle is set high when you start the car to heat up the catalytic converter and the higher rpm may be causing some of the problem. Just a thought....

nyca

It's normal as far as I am concerned. It's not a "jerk", the first 1-2 shift off a dead cold engine causes the RPMs to be held just slightly higher. And its only the very first 1-2 shift, you really have to listen carefully to notice it. I think its some kind of self check the gearbox is performing. It could be an emissions thing, but why is it only the very first 1-2 shift, the next 1-2 shift on the same cold engine doesn't exhibit this.

I have never tried letting the car idle and warm up before pulling off, to try and determine if its related to engine temp or something in the transmission.

nyca

correction here, its the very first 2-3 shift that does this, not the 1-2.

I let the car warm up completely today before taking off, it still holds 2nd a bit longer before making the very first 2-3 shift. So its not an emissions thing.

len56

the seven speed shifts like a human, really quickly for a standard auto (not compared to a dual clutch lol)

tivoboy

I get a bit of a jerk/lerch, but when going DOWN from 3 to 2, in automatic.

ET_Skipper

I left the car at the dealer yesterday night so when they work on it today the engine is cold.

The dealer said it is because of a delay in shifting gears. They called Mercedes Benz and MB did not let them do anything in the tranny. They said they are working on a software patch to solve the problem and when the software is available they can install the software. No ETA.

Thoughts?

Glyn M Ruck

Sounds like BS - There have been several software updates for the 722.9 transmission & they need to flash the latest.

What I don't understand is you say it does it in both C & S. Then it's not the 1st to 2nd change that is jerky. In C mode the car pulls away in 2nd. Our 7G is absolutely smooth. These cars do hold gears longer when cold to heat the CAT quickly.

ET_Skipper

it is the first transmission shift whether it is from 1st to 2nd in S mode or from 2nd to 3rd in C mode.

Any advice on what I am supposed to tell them? "Please look at it again" or smt else. Shall I maybe call MB direct line or smt? My tranny is very smooth too it is just this first shift when the engine is cold

Ausmbtech

If you ever got the chance to see this transmission in pieces, it's an incredibly simple transmission. The hard work has gone into the basic design and it truely is engineered simplicity. There is no small parts to break in this design, they eliminated most of them back when the 722.6 came out in 1995/1996 and they got rid of the rest when the 7 speed came out in 2004.

Most issues are solved with software and a good tech who can listen to your complaint and work out the best solution.

As for long term ownership, they are very reliable!

jangy

valve body...