albania

hello
when at position N the gears are not activated so the RPM and the engine sound is quiet
but when stopped with brakes and the gearbox in position D or R ( in traffic for example) the engine is not quiet anymore and has also vibration and seems immediately ready to go,
with brakes pressed, the car have higher RPM when changed from N to D or R
this is happening also in other mercedes I have tried but not in all of them
maybe it is something not calibrated enough

for example on VW golf mk6 I used to drive it is, perfectly quiet engine sound when brakes are pressed and on D, and just when you start to release the brakes, then it started to have higher RPM. I understand that the technology is different but the concept maybe is similar

shadenfroh

How many kilometers on the car?

Your engine mounts are most certainly bad, few people in our part of the world change them before they vaporise. They cause vibrations from the engine to travel through the chassis and produce sound.

It's normal for the RPM to drop when you engage D or R and be slightly higher in N. You say yours does the opposite?

albania

200.000 km
it is 2 months ago that I have this car and I dont know the service history
yes the RPM drop when engaged on D or R but it starts shaking and the car want to escape from the brakes
when I am in traffic I feel uncomfortable if I keep D engaged, I should put on N while staying 20 seconds still

shadenfroh

This is a very basic question, but still I must ask: is this your first car with an automatic transmission? Creeping forward is normal behaviour for an automatic.

albania

no its not my first automatic
15 years ago I had an old mercedes W123 that had the same behaviour like this one
I had a bmw 1994 318i that was just fine
another W124 automatic gearbox and was just fine
I have now a skoda yeti dsg 2013 also a 2012 Vw golf VI dsg, that are just perfect, you engage D and are standstill without any vibration, when you start to release hte brake then it engages electronically the gears and then it change the RPM

so
I think my w211 has something wrong, not serious
and should be something easy to fix, but I need to find what

shadenfroh

Honestly, I've never heard of what you're describing, so I'll refrain from further comments on that matter.

As for the vibration/noise issue - have a look at this video to test your engine. You can clearly see the difference between one mount that is good and one that is shot:

OrientBlau

(I posted this in an unrelated thread)

I have the same issue.

I just bought a 2011 C300 4Matic and it runs great except for this slight vibration I feel in D or R. It goes away in N, P or "at moving speed." While waiting at a traffic light in D, The vibration disappears once you stat moving or shift out of gear into N or P.

The other day, I had new engine and transmission mounts installed. While the vibration is much less than before, I can still tell it is there. The mounts just help mask the vibration. They are not the cause per se. My old mounts were not really bad.

Since I purchased the car, I've been combing through the threads for similar issues. It seems that those with these symptoms have all gone ahead and replaced the three mounts. While it has solved the problem for some (likely b/c they indeed needed new mounts), many 4Matic owners (not just he W204) have not had this resolved, including myself.

there are some threads that allude to the drive axle and drive shaft particular to the 4Matic. Some have had this expensive repair cure them of the problem. Another seem to have needed a new transfer case.

Anyway, I'm subscribed to this thread now and hope others will report back with their results. While there are many threads out there about this issue, many posters do not bother to follow up with what fixed the problem.

One more thing.

What I do notice, is that depending on the incline of the road that I am on (while stopped in D at a light), the vibration *seems" to diminish to noting, while other lights it is constant. I'm not sure if the wheel position may have something to do wit this.

There is also one other issue now that I think about it. When I first got the car, it had the vibrations, but it also had this steering noise and vibration as well. IF I turned the wheel as it nears the travel stops, there was a shudder-like vibration too. Now that I have new mounts, the vibration is less as mentioned, along with much less shudder in the steering wheel when turned towards stops. Like the general vibration, the steering vibration is still there but much less. The mounts are holding/masking some issue together. These two symptoms are likely related.

albania

my feeling is that the newer cars has an electronic way of gear engagement
if you engage D or R it will be done electronically after you start removing the feet from the brakes ( like this is done on my vw Golf mk6 2013 )
and meanwhile my w211 2005 has the function mechanical immediately after you engage the gear lever to D or R
do you think the same ??

shadenfroh

I decided to read about your Golf and I now see how you got confused.

You Golf has a DSG gearbox and not an automatic transmission. What you think is a gear engagement after you lift your foot of the breaks is the one of the clutches starting to bite.

https://en.wikipedia.org/wiki/Direct-shift_gearbox

722.6 is fully electronic, but you have the old-fashioned gear shifter. The shifts are neither immediate nor mechanical. The car can refuse to take the input of the shifter (for example - if you slam it in R while moving forward faster than a certain threshold, it won't engage reverse), it can shift to neutral regardless of shifter position and so on.

albania

I know about the DSG, I am not discussing about the gearbox, but just the strange vibration with my mercedes
as I didnt know how to describe it, I mentioned the golf
but maybe now you have an idea what I am asking; why it is immediately engaging and immediately makes vibration, only if not moving the car.
When it starts moving it is normal, without any vibration

shadenfroh

I understood your question and answered it in my first reply. The number 1 sign of engine mounts deterioration is the appearance of vibration with R or D engaged.

Basically the mounts are not effective in that RPM range anymore. When you drive off engine vibrations naturally become less pronounced with the higher RPM.

albania

yesterday happened something new
when started the car, I was moving the steering wheel and directly the car was shut down, strange for an automatic, then I realized that maybe the steering pump has a problem and it creates additional efforts to the belt and cause this.

Does it have any relationship with the engagement of the gears, so maybe this was also before that caused shaking (or was a combination with moving the steering wheel and changing the shifts)
or doesnt have any relation between aux belt and the gearbox?