Pete7874

52K miles on the car. A week ago the car was at the dealer. It had a slight trans fluid leak, so the dealer replaced one of the seals/gaskets on the trans. I'm guessing they had to take the trans apart to some extent to get to the gasket. Ever since, I noticed that the trans shifts in a more abrupt/jerky fashion. Not overly so, but still noticeable, mostly in lower gears (1-4). Before I go back to them and complain, and before they try to tell me that "it's normal", any ideas what they could have screwed up while putting it back together?

They also replaced motor mounts during the same visit, but I don't think that would have affected the trans shifting.

RavenMDX

same mileage, just had my trans fluid changed and started to notice some light random shifting jerks when slowing down to a stop sign. I've heard others having similar symptoms after trans service. What is causing this?

wally AMG

mmm maybe they switch your transmission From "C" to "S" sport setting star more "abrupt" since start in first not in second did you check that ?

Pete7874

I was comparing the "S" mode operation, both before as well as after the service.

I'm wondering whether the trans is low on fluid. Maybe they didn't refill it properly after the gasket change. I've heard that trans shifting can be harsher if the trans fluid is too low on some cars. Sadly, there is no way to check trans fluid level on this car, so it'll have to go back to the dealer.

Cillys

Now we know why its called the stealership!

snowmuch

I got my transmission service done recently too. Now my car feels little bit slow(or smooth) whatever you like to call it. It's not responsive or aggressive as before

beneliezer

Ok-

They likely reset your throttle adaptations. Look at your invoice and verify...

Normally after doing any type of transmission work they will reset the adaptations which will prompt the car to "relearn" your driving style.

I believe the adaptation range is 75 miles.

Have you put enough miles on the car since the service to re-teach the computer?

RavenMDX

good point but I did hit this range a few days ago. I had this checked at the dealer today and of course they didn't find anything wrong with the shifting/downshifting patterns

beneliezer

Is it possible you were too consumed with the jerkiness of the transmission while it was adapting and tried to compensate for it? This could result in "learned jerking"...

There's a DIY on the board for resetting the adaptation. I would at least attempt this one more time and try to drive as normal as possible for at least 75 miles before bringing it back to the dealer.

RavenMDX

Spoken like a doctor, you may be right. Is this the ECU reset or something else I need to do?

RuskiBenz

with car off put key to position 2 right before start than press and hold the gas pedal all the way down for 10 seconds while still pressing turn off and take out key and take your foot of the gas pedal wait 5 mins or so and its reset

Acapulco Bill

There is so much misinformation. What RuskiBenz described is just an accelerator recalibration and has nothing with either the TCU or the ECU, although the position of the accelerator is one of the variables affecting both.

A variation of this of course is to only depress the accelerator half-way on resetting, this calibration technique causes a more aggressive adjustment.

Recommended is to check for the latest TCU software update, for 7G's manufactured before mid-2010. The immediate improvement is fantastic, as it resets the "Adaptive Learning", however in a few hours the 7G will be back to its old, sluggish and slow-shifting bad behavior.

beneliezer

Where exactly is the misinformation here? Do you disagree that this is an adaptation issue?

Acapulco Bill

The words used for "resetting the adaptation", imply that in any way the "Adaptive Learning" memory of the 7G's TCU can be reset by the owner. It cannot. Many, many DIY threads concerning what is actually an accelerator recalibration begin by stating that this procedure is a "reset of the TCU", which is misinformation.

As mentioned, the TCU software update for pre-mid-2010 7G's can reset the flash memory of the "Adaptive Learning" during the update process, but does not disable the "adaptation", as driving in city traffic after this update is performed will return the 7G-tronic to it's evil ways within an hour. There is hope, however, as several tuners offer upgrades to the valve bodies and a new TCU that solve this situation (also the "jerkiness" subject of this thread, as the modification provides higher pressure valve bodies that lock the plates in more firmly, the "K" clutch and "B" brake plates grab firmly under highest pressure and therefore do not shudder or jerk). Originally developed to solved the problems of the lame 7G version found in the C63 AMG, the valve body and TCU change can be made to the other two variations of the 7G-Tronic.

Information is here: http://luxurycarmagazine.com/a-solut...onic-troubles/

And a firm offering this upgrade is Weistec: http://www.weistec.com/7229vb.html

These are the only routes to "resetting the adaptation", and not the DIY threads which confuse owner TCU management with accelerator recalibration.

beneliezer

I'm pleased to see how much you know about the 7G. However, in looking over your materials, it doesn't appear that the OP's vehicle is on the supported platforms list

Acapulco Bill

Weistec in a separate email, stated that as the valve body assembly was identical on all three versions of the 7G (300nM, 500nM and AMG), the upgrade and new TCU could be performed on the standard W204.

However, I did not ask about the 4Matic, so yes perhaps this is not a solution for the OP.

Bosnia1992

I have this issue but they failed to change the oil before selling it as CPO to me and I'm sure other services aswell . It's still there from gear 1-4 and was told its normal and now I have an engine whine upon accelerating aswell. Any suggestions?


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Pete7874

I'm the OP. Time to update this tread. Since the more abrupt shifting wasn't going away even after a few thousand miles, I took it back to the dealer (actually I was there for Service B anyway), but they said it shifts "normal".

Then recently the car developed a constant whine noise from the front end while driving. The wife just took it to another dealer - they say the car needs a new transmission. 60K on the clock. Pathetic.

c3002008

omg, that is bad news, we spend our hard earned money on the three pointed star in order to have a reliable, long lasting car but these trannys commonly have issues. btw how much is the dealer charging you for a new tranny?

Pete7874

Extended warranty paid for it, so I don't really know. But I wouldn't be surprised if it's $7K-$10K, parts and labor.