xflair89

Hello fellow Benz connoisseurs

I'm in a bit of a pickle and i cant figure out what the issue is, so figured id come here and ask all you smart people to help me diagnose my problem.

My 2010 E350 vibrates when in last gear (Gear 7) at high speeds, under load, (over 60mph, appx 2,500rpm) throughout the body of the car. All passengers can feel it in their seat. When i throw it in neutral while at those speeds, the vibration stops, and when i lower the gear (any gear lower than 7) the vibration also stops as it revs higher. When parked and I rev the engine (about 3 - 3,500rpm) it also vibrates. My brother seems to think its the Harmonic Balancer, but there is no way to diagnose it without buying the new part, installing, and seeing what happens.

All the other gears at the lower speeds don't vibrate like that, hence the cause for concern. The vibration is like a rhythmic, pulsing feeling. Like waves? Hope that makes some sense.

So my questions are:

1. Is it possible that the last gear is somehow damaged in the transmission? (Gosh i hope not)
2. Could it really be the harmonic balancer?
3. Long shot but, could it be the wheels? (Tire shop told me i had bent rear wheels when i did my alignment and balancing) Although that wouldn't explain why it happens only in Gear 7

Thanks again everybody!

Please help put my mind at ease

KEY08

Gear 7 at 2.5K rpm it shakes and when sitting and revving to 3K rpm, so how can you put the blame on the transmission? Could be your motor mounts are completely shot since it does it while you are sitting still. Maybe your drive shaft is also out of whack causing the shake at speed. Bent wheels also really affect these cars at speed. These E Class cars are designed to go 140mph all day on the Autobahn with no drama. How many miles are on your car? Are you the original owner with all service records, so you know what has been replaced?

xflair89

The only reason I felt it could be a transmission issue is because of its strange behavior of only happening in a specific gear When sitting and revving, the vibrations aren't as severe as when moving, so that was a wild guiess

I also thought this too, but when motor mounts go bad, doesn't the engine dramatically shift over when revving? Like lifts off one side? Mine doesn't seem to be doing anything that crazy.

This is an interesting one... Hadn't thought of it. That would suuuuck

This is true, but the specific gear thing kinda disregards it. Coasting at high speed reducing the vibrations, so its only when in gear.

The car is aging fast though, now at 120k miles. I don't know what all has been replaced on it though, im the second owner

Mud

Motor mounts that have actually separated can allow the engine movement you described but if I remember right the mounts in these cars have hydraulic fluid in them? If the fluid has leaked out then I believe you would experience vibration from the lack of dampening.

KEY08

Yes, they are hydraulic oil filled mounts and they have a history of failure or lasting less than one may expect. Your car has 120,000 miles. If you can't get records of prior service, get the car on a lift and check out the mounts. I would start there. It will shake at speed and will shake while parked as well.

kbob999

FYI - the motor (and trans) mounts on my AMG's lasted only about 80K miles. At 120K, I would bet that is your issue.
They don't separate, but settle the engine in the frame so it is 'bone on bone'.

I've done both of mine DIY, and I'm sure others have done the W212 here. My W212 will probably need them in a year or 2. Best done with a lift, and with a floor jack to lift the engine (one side at a time).
Probably a 4 or 5 on a scale of 10 for difficulty. One special 16mm wrench is required to remove the bolt from the top of the mount.
Otherwise it's just 2 bolts to remove and replace them. Might have to drop exhaust to pull the mounts from the back. Search the forum for this.

Keep us posted on the outcome.

Mud

I should have added that engine and transmission mounts were replaced on my car under warranty, I think it was around 30k miles.

300SE1993

I had a vibration in mine in high gear at around 40-50 MPH. Changing transmission fluid solved it, but I did not have issues in neutral.

ItalianJoe1

Motor mounts and trans mount, replace them and you won't believe how smooth it gets. They collapse with age, I normally see them at 30-40k miles they are bad enough to feel, they will be almost a 1/2" shorter than the new ones when you take them out. Cheap/simple repair too unless it's a 4-matic, which isn't bad just takes more time.

xflair89

I'm actually going to flush out my transmission next week. Will report back on how much it dampens my vibration issues


I'm also going to change out my transmission mount, seems to be the easiest to get to, and see how that works out

Can't really seem to find a good step by step tutorial on the Pre-Facelift w212 to get the Motor mounts out. Just found the Tranny Mounts Tutorials though. Mind lending a hand in finding this?

belarus27

I had intermittent vibrations at 65-70 mls hour , come and go , couldnt figure out what that was... alignments , new tires , most of the suspension parts are new as well.
until i got my transmission fluid and mount changed last week.
Cant feel those vibrations anymore.
i just changed one mount on trans... i would suggest to do a fluid change and both tranny mounts while u at it though.

300SE1993

Someone posted one on here a while back. If you do some searching around, you should be able to find it. Also, I did a drain and fill (pan and torque converter) with filter change. I did not do a "flush".

There's one transmission mount, and two motor mounts.

Kilt

I had an issue like that with a Mustang. It vibrated at a certain RPM but not above or below it. The problem was the harmonic balancer. The indy shop had a used one that they gave me for free and installed for a very small charge. I don't know how difficult it is to replace the part on an E350. RockAuto sells one for about $260 for an E350.

xflair89

Ladies and gentlemen, my issues have been resolved!

So after a lot of driving, this forum post, and paying attention, I narrowed it down to my front wheel bearing, bad. tranny oil, and transmission mount! I was pretty sure the engine mounts were okay because I did the engine load test (putting car in drive, foot on brake, and checking amount of play the engine had when I press the accelerator). Also a tip, bad engine mounts can be felt when you put your hands on the engine and rev it. Tranny mount is bad when the engine doesn't vibrate, but you feel the vibration under the car / floor of car while you rev and sitting in it.

The wheel bearing caused a rumbling / grinding-esque feel to the car. After jacking up the car and spinning the wheel, the brake disk slightly wobbled, but those were new, so figured it was the bearing. /looking at it now, it was for sure the factory one, so I replaced that. The wheel had no more grinding and wobble:



w212 bad bearing


Then I replaced the tranny mount. 5 bolts total, super easy job. A little tricky if the tranny shifts a bit when I jacked it up, and lining up the holes but done in 45mins. The mount was definitely collapsed, and had cracks all over it. This one mad the biggest difference



w212 collapsed tranny mount

Lastly, I did a transmission fluid change, filter change, and gasket change! Now it shifts like a dream! No hesitating shifts, slow shifts, nada. Just how a w212 should feel!

Thanks for all the posts here, helped me a lot! Hope this helps someone in the future!

KEY08

JohnnyGrand

Hi Belarus27! I noticed you have a 2010 E550. I have a 2014 E550 with the twin turbo and am noticing some random/occasional vibration in the floor/gas petal at higher speeds. I was told the motor or tranny mounts are even worse on the 550’s (V8’s), is that the case? I like you have had all my tire, suspension work done so can’t seem to figure it out? I noticed it got a little worse after I did my tranny flush. When I got an alignment a few months back a mercedes tech said I’ll need mounts soon. When I went back for another service a different tech said my mounts are fine. Maybe I’ll start with the tranny mount like the other member did.

MBNUT1

Typical symptom for bad motor mounts is in gear idle vibration.

JohnnyGrand

Thank you for your reply. I’m not getting vibration at idle. Today I also changed the tranny mount and there’s no difference with the vibration. I feel it at high speeds still in the gas petal and floor, and sometimes at really low speeds when I’m in 7th gear and when I accelerate in low torque range 1200 or 1300 rpm, I accelerate slowly and feel vibration. I took pictures of my motor mounts and the oil filled cylinder wasn’t collapsed where it’s metal on metal. I did the test where I hold the brake and hit the accelerator and the engine moves but I don’t know what the tolerance is or how much it should move?

belarus27

Yeah in your case id stsrt with tranny/engine mounts...

300SE1993

You mentioned you had a transmission fluid and filter flush done. Did they user the correct fluid? Was the torque converter draned also?

nota_amg

I now this is kind of a weird question, but do you still have the old mount? I am wanting to attempt to build a urethane trans mount and need an old mount to tear up. If you do, would you consider shipping it to me? I'll provide postage and a little on top for your troubles... predicated on your car being a sedan, that is.

belarus27

both engine mounts*

babalehleh

E550 2014 4matic.
​​my car and steering wheel is shaking between 20-40mph. Mostly when i let go of the gas and crusing and when its under load. After 40mph it goes away. Ive reseted my transmission it improved just a bit but not fully. The car shakes but not the steering when giving it a kick at about 80mph. Dealership has changed all 4 suspension bags and back struts, control arms, tie rods, engine mounts, transmission mounts, cv joint, differential ,steering rack and torque converter. Tires and rims are brand new. Theyre saying they cant find the issue. What else should i be inpescting? Transfer case? Driveshaft? Guibo? Center bearing? If anyone could help, that would be great!

MBNUT1

General question to the forum members. Can cars be run safely on a lift?

babalehleh

Dealership told me they did a in air dyno and wheels are not running straight .theyre telling me that there is some vibration from the steering angle sensor to the steering rack.