Hello,

I have a 2014 E Class Coupe e250 (petrol) facelift with 108k kms, with full service history. I got the car at 79k kms, approximately 2 years ago. I came to ask for a second opinion on what should I diagnose next as I have the following issue: when I start the car, fresh in the morning, I wait the 30 seconds to 1 minute and then place in drive or reverse, I get a small shock and if I keep the brake the car vibrates. I can hear it, if I test this with someone I can see the engine vibrating, and I can feel it in the passenger seat (especially I can see the headrest vibrating) and I can feel it in the back seat floor (mostly on the right side). I cannot feel the vibrations from the driver seat/floor.

This vibrations lasts until I drive 15 to 30 minutes in the summer, it lasts longer in the winter. The vibration disappears some time after the engine has reached its operating temperature. That makes me think it's related to something taking time to heat up and perhaps expand. I get no vibration while driving.

My initial presumption was that it's something related to the gearbox, specifically the torque converter, as it happens when I get the gearbox engaged. I took the car to several reputable gearboxes services and to a dealership and they all told me that the gearbox has no errors, all parameters are fine, and it's working perfectly.

I changed the oil in the gearbox when I got the car at 79k, without knowing it was already changed at 60k (found out later). I changed the engine and gearbox mounts 2 years ago, and the gearbox mount recently again as some mechanic told me they were 70% done.

During my last visits to all the shops I got several possible options like: the shaft mount/flex plates, an engine that runs inefficient while cold due to carbon deposits on the throttle body/valves or the rear axle shafts.

What are your suggestions, what could be the source of this vibration?

LE: Even tho a lot of the shops told me the gearbox has no problems, it still has every now and then some rough downgrades, 3 to 2 especially, and sometimes when the gearbox is cold and I come to a stop I feel a vibration like I'd drive a manual and would not release the clutch - probably the lockup clutch in the torque converter remains stuck a bit. With this being said, the shops still told me 'it's normal for a 7g tronic'.
LE2: replaced spark plugs + ignition coils recently, no change

 

Your engine + tranny mounts are new as well as fresh ATF service. Yet idke vibrations are felt.

This is caused by your engine not running smoothly at near 100k Km.
Deal with ignition tune up: plugs + boots.
Replace oil at 5kMi (NOT only at 10kMi).

Upgrade your oil to help get balanced cyl. contributions ie. noticeably zero vibrations.
Else power gets lower and throttle more spongy from lean A/F mixtures.

7G Tranny is 100% fine unless clutches are repeatedly abused with high-heat shifts.

 

Replaced spark plugs and ignition coils recently, I did an update in the initial post as well. My services are done at 8k kms (5k miles) or 1 year.

What oil would you recommend? I service the car at dealership so the oil is whatever the dealership is using for the car, whatever Mercedes recommends.

 

You're getting the best MB service possible.

The official dealers can not perform non-standard service procedures.

I would use upgraded PAO true synthetic oils such as MOTUL that are on the "MB Approved" list.

 

Do you know if your mounts were aftermarket or OE? For your gearbox mounts to be 70% after two years tells me something is likely wrong with the set put in two years ago. Vibrations you are describing are usually from mounts so I think the engine mounts are failing if the gearbox mounts are 70% done after two years.

 

They were OEM. I read too many stories with aftermarket mounts failing after 3 months so I went with originals.