Hi Guys,

I have an 08 s550 4 matic with 90k miles. Recently the car starts a vibration only when the car is stopped with the brake applied and in drive. Once you put it in neutral vibration goes away. I just changed the 2 motor mounts and the transmission mount and the vibration has gone 50% away but not totally....does anyone know what it could be? Please help and thanks in advance!

Misfire would be my guess. When you put the car in neutral, the rpms likely increase due to the load being taken off the engine, which may hide a minor misfire.

I found post 42 intriguing

https://mbworld.org/forums/s-class-w...e-mystery.html

Hmm.. Front axle not moving but causing a vibration? Not likely.
Using the same logic you could replace the tires to solve the idle vibration. In jacking the car up and replacing the tires you might incidentally change the vibration, but when the car is stopped axles don't move, tires are not turning, wheel bearings... You get the idea.
Same thread notes that a throttle body relearn solves this.
Misfires would be expected to show in a star scan but perhaps there's some threshold where it won't show.
Spark plugs might not be a bad idea if they're due.

Warped rotors ?

Please ignore it , I just posted just looking at the title only ,no delete button

I found and fixed the problem! Finally! My CV joints were bad, Both of them in the front. After changing the Motor mounts the last thing it could be was the CV joints. It does not make sense as the mechanic was even shocked the vibration went away. It drives like new now and no vibration!

That's great , thanks for the update