OCD_enthusiast

Car has more than 500000km on odometer mostly on open road, serviced at authorized MB dealership since day one. I own this car for one and a half year and some 20000km. Other than this issue car is running great. This issue is mostly notable during rush hour city driving and gearbox is in "E" mode. My guess is that in "S" is not so noticeable since engine revs around 2000 not 1000. Shifting in lower gears is not fill always smooth as I fill it should be. I'm on top of this issue since day one, read everything I could find on internet. After reset transmission adaptation is done there were noticeable improvements, but not resolved completely. Engine mounts are somewhat worn, but not for change. There are no error codes in ECU. I convinced myself it is normal behaviour for this model until I saw on youtube dashboard videos of other cars that they habe much faster rpm change (even drop in rpm is faster then mine). Could that be an issue? It really does fill like engine does not respond with rpm change fast enough (increase or decrease) to both my (gas pedal) or transmission request, but I connected that with throttle-by-wire and ECU trying to be smart with throttle response. Now I'm not so sure anymore.
Here is video of my dashboard recording: flat road, cruise at 50km/h, manual gear shifting between 2nd and 3rd gear. Shifting is not ideal, it feels like engine is slow to adjust rpm for new gear ratio. Rpm change is done in two steps:

• when shifting down: rpm from 1850 first raise to 2450 and then settle at 2850
• when shifting up: rpm from 2850 first drop to 2000 and then settle 1850

I'm convinced it should be more precise: when shifting down from 1850 to 2850 in one step, when shifting up from 2850 to 2850 in one step. Both fast enough not to loose car speed. In 3rd to 4th and higher ratio it's one step rpm change, not in two steps. In 1st gear kick is also noticeable, especially if car is not standing but slowly moving (like in traffic jam column).

KEY08

500,000km=300,000 miles 😳
I’m surprised it’s still on the road!

S-Prihadi

I guess at 500K KM, the lock up clutch is already worn out. If the tranny never gets total overhaul yet since new, its a good time to have it now. This is amazing, 500K KM

OCD_enthusiast

I'm aiming for 1M.
I look at the internet for symptoms of worn lock up clutch and could not find many. The one I found explains lock up clutch is used to mechanically connect engine with gearbox on higher vehicle speed thus saving energy. I have no issues on higher speed. Only in 1st and 2nd gear changes which usually occurs well below 50km/h.
I also do not recognize slippage. Transmission and mounts was my first point of attention, but this unprecise engine revving during gear changing behaviour made me suspect on something relate to engine. Does dirty valve control body could create these symptoms? I also have minor trembling on idle, assumed it is due to partially worn engine mounts, but found this guy fixing it by cleaning valve control throttle body Edit: last sentence valve control to throttle

S-Prihadi

Yes, dirty or worn out valves at valve body surely can do those unwanted mechanical issue you have.
After all your tranny is oil operated, which the oil flow is allowed by the valves in the vale body assy.
Engine mounts surely bye bye by not even 500K KM on authobahn. Take a photo of it from side view, it is easy to see a collapsed engine mount.

Below is a collapsing engine mount. Black rubber wide flap touching the protrusion of the engine mount body right side. If good mount the gap is much wider between black rubber flap to the the protrusion of the engine mount body




I replaced engine mounts as fast as I wear out my rear tires, under 20,000KM. I am super sensitive to vibrations.
Below is my 2nd engine mounts replacement, 1st time replacement at approx 10,700KM and 5 years old. I am abusive for kickdown, WOT and high speed jump on my crappy highway where bridges joints is for rally cars hahahah

18K = 18,000KM



18K = 18,000KM



18K = 18,000KM



Try to watch this videos, perhaps it may make you understand better which part of the 722.9 7 speed tranny will wear out, so you can have a better repair direction

Dont think auto tranny has no clucthes


.
Valve Body - Conductor Plate


This one is an acceleated tranny wear by AMG owners and tuned too...


Clutch wear. 300K KM

OCD_enthusiast

These are great resources and valid remarks. I will look into it for sure. Now I know how to check state of my engine mounts, I will share photo when I make one.
I edited earlier comment for clarity: I meant throttle control body.
Transmission was my first suspect, specifically transmission mount. But it is OK. In first days, kickdown was far worst then now: it felt literally like someone kick your kidneys. Now its much better but not perfect. I cannot explain the reasons why it's condition has improved apparently on its own...
I'm aware that dirty solenoid valve on transmission control valve could be the cause, but according to internet when valve is the issue it only misbehave when car is just started (cold). My issues are consistent accross cold/warm engine or external temperature. It is the same when start the engine and it is the same after 200km ride.
Lot of other drivers try to fix this gers changes "jerking" with interventions on transmission and most of them reporting issud if solved is back after few days. Eventually they drop it since dealership also does noz recognize it as an issue for repair.
That is why I'm looking at other direction, I do not have money to throw away on expensive transmission repairs which will not solve the issue. If transmission is good for overhaul, that is OK, but I need a way to confirm that before dismantling whole transmission....

Left Coast Geek

I often put our 2016 E350 4matic in "S" at low speeds in urban traffic, the higher RPMs just drive smoother, especially 2-3-2 kind of shifts at very low speeds, like you started to accelerate gently, the car is in 2nd, you have to let off for a bit, it jumps to 3rd, but then you give it a little more throttle again so it goes back to 2nd kind of abruptly.. on open roads, I revert to "E" mode. our car has like 38000 miles, when we got it a year or so back, it had 28000 and it was still like this.

OCD_enthusiast

I'm kindly asking other owners to observe rpm gauge when they shif gears: is it fast and precise or it looks slow, unprecise with additional asjustements in rpm (as in my video)?

CaliBenzDriver

what, you want to shift 2nd gear @50Km/hr.... try shifting 4th instead to see how things improve.

1st and 2nd gears are used to pick up from a dead stop. Leave those gears alone at higher speeds....

They are only good up to 10Km/Hr unless you want to redline your way to blue smoke...

Left Coast Geek

note different versions of the 212 have different final drive ratios too, so it would be better to talk about RPM than speed. 50 km/h (30 MPH) is pretty high reving for 2nd gear. What Cali said, 1-2 are for getting rolling from a dead stop

OCD_enthusiast

Since no issues in higher gears I will accept this as normal behaviour. Thanks everyone.

Left Coast Geek

even when my cars were 4 cyl 5 speed stick shifts, I didnt like to really lay on the powere until 3rd. full throughttle 1st gear launches mean lots of wear and breakage.

OCD_enthusiast

Guys, you are completely right. Purpose of attached video is not to be example how car is supposed to be driven, but to set conditions for clear demonstration of imperfections to be captured on video recording. Same imperfections are present in other situations:

• When roll from standstil (engage in 1st or 2nd gear) not noticable at all!
• When barely moving cca 5km/h slowly pressing gas pedal kick is noticable when gearbox connect engine to wheels and this happend frequently when you are moving in traffic column and cannot be avoided with E or S or manual shifting as it simply has to happend
• When upshift/downshift in 3rd, 4th, 5th, 6th, 7th as gear is higher kick is even less noticable, completely dissapear after 3rd to 4th and above

I believe issue (if exist) is with engine rpms and not gearbox.