MDMercedesGuy

Have any of you experienced any shift flaring with a 2012 yet? 4,500 miles in and I experienced one this morning.

This morning I was turning out of a parking lot for the first acceleration of the morning, accelerating moderately to about 45 mph and on the 2 -> 3 upshift at ~3600RPM, it flared to about 4,100RPM and then caught itself.

Mine occasionally acts a bit stupid - taking excessively long to downshift if in E and you stick your foot in it (well over a second from the time you press the accelerator until the time it kicks down) - etc. It makes me pine for a clutch pedal again.

I haven't had it do this before, but in about 6 hours I am going to begin 2 weeks of travel that are going to put about 1,500 miles on the car. I'd rather it not be acting stupid at 4 months old right before a lot of travel.

scottjlake

First of all, it's more than likely a software issue...

I did a 4-5 year stint with MB as a service advisor and this is usually the cause for most transmission problems. Have it addressed with your dealership at a time that is good for you. Otherwise, treat it as a minor annoyance and just get over it.

Very rarely would it be a physical/mechanical problem with the transmission.

Enjoy the car, don't stress over it!!!

Glyn M Ruck

Monitor it & if it continues get the dealer to reset all adaptions on the tranny.

PorterFNU

I'm having a similar issue with my '08 C300 4matic. Bought it used with 18k+ miles The trans needed to be replaced at around 32k miles because of a bearing deep inside the trans going bad. The dealer's service advisor said it was cheaper for them to replace the whole thing then to fix it. The problem started with the car being a little jumpy when shifting. It then started grinding because of the bearing. After the new trans went in the car has always seemed to make a whining noise but has otherwise been running pretty good. Although I was always waiting for the other shoe to drop. I've got 83k on it now and the shoe finally dropped. I was 400 miles from home when the car went into Limp-Mode (I had no idea what was happening at the time) engine shuddering, trans not shifting, no power. Stopped the car, ate lunch and then restarted it and it started like there was never a problem. I'm nervously waiting to see if the trans will finally drop out before I can have someone look at it. I'm long out of warranty so anyone have an idea as to what horror I'm in store for?
On a side note, the cam adjuster sensors needed to be replaced at 19k miles. The CEL comes and goes almost on schedule. A buddy has a code reader and it's the same code again. Those are the two major issues with the car.
Thanks for any help you can give.

MDMercedesGuy

Thanks for the replies everyone. It acted up once, yesterday morning - but I caught it too late. I drove about 375 miles this weekend - mostly 2 lane country roads at highway speeds, with a few passes that took it to redline.

The extended driving seems to have helped it a bit - almost like it is an issue with adaptations/software like you guys said. Unfortunately because of traffic patterns and such around here I am either stuck in bumper to bumper traffic or screaming down the highway, so it's probably rather confused at the rather rapid changes in driving style.


I'll keep an eye on it and have them look at it next time I have it in for something.

Glyn M Ruck

I would not loose sleep over it. If it continues they just need to check that the clutch pack closing pressures are in spec & recalibrate them if not.

tasho3

I'm on the same boat. It's either bumper to bumper downtown or doing 70-80 driving to suburbs. and it usually flare shifts when I first start it up in the morning, once its all warmed up and lube gets flowing everywhere, it runs perfectly fine

Ben'sBenz

If it's on it's second transmssion and already needing a third with less than 100K miles, I'd be trading it in the next time the CEL is off.

300SE1993

Good to know this flaring happened when these transmissions were brand new. I have the same thing on mine with 100K miles. I won't worry about it now.