vahid123ir

Hi everyone,

I drive a 2008 MB C350. There is a propeller noise coming from the front middle of the car for a while. The noise sound like a rotating metal piece rubbing against another part. When driving low speed the noise is more obvious but even in high speed is still there.
Car also has the constant abnormal vibration when driving or in idle. When I change the gear to Neutral the vibration reduces but it is still there.
I'm not sure if it is related, but recently when I turn on the car, the rpm starts jumping from around 500 to 1200 rapidly for few times and when I start driving it kinda stabilizes.
Also, when slowing down to stop at the traffic light car goes through couple of of jumping and jerking before it stops. This jumping and jerking feels like the car skips to stop and then stops.

Couple of mechanics have looked at it and diagnosed different things. One says the bearing needs to be replaced another says is the Torque Converter. The maintenance recently done on the car are:
- Replacement of Front Drive Shaft
- Transmission Fluid change
- Manifold Intake cleaning
- Power train maintenance (Break Pads, Rotors replacement as well as Caliber maintenance).

I'm wondering if anyone else has had similar issue.
Also if you know a mechanic specialized in transmission particularly for the MB C350 in the GTA area (Toronto) that I take the car to for further diagnoses.

Thank you in advance!

Rudeney

Does it do this in park? If not, then I doubt it is the torque converter as it is still rotating. If it does do it in park, it would not be any driveshaft components as they are stationary. And if it does do it in park, then it could be a cracked flex plate (a.k.a. flywheel). In that case, has the engine or transmission ever been removed?

vahid123ir

Thanks for your reply Rudeney!
Yes, the noise and vibration exist when in park but noise is not as loud and noticeable as when driving with low speed.
In fact, when my mechanic changed the transmission fluid, he mention something that transmission has been worked on.
If the issue is with he flywheel, do you think it will be ridiculously expensive to have it fixed. Is it even worth to spend money on it?
Any trusted mechanic you may know that I can take the car to to have it checked?
Thank you!

Rudeney

If it is the flex plate (flywheel), it requires dropping the transmission to replace. With the proper lift and tools, it's not a huge job, maybe a day's work for a skilled tech. I would not go to a dealer. Find a good indy. And ask this question: "What special process to you use to properly seat the torque converter and keep it in place when re-mating the engine and transmission?" If they blow it off, go elsewhere. If they give you something that sounds reasonable, like they understand how critical this is, then they should be good to use.