I recently purchased a used 2007 c280 4matic. When I let my foot of the excelerator at low speeds there is a grinding sound and when I press the excelerator it seems to be gone it also seems to be more noticeable when the car is first being driven and less after driving for a couple hours. It sounds like its coming from the center of the car. It only seems like the sound can be heard inside and not outside, when the windows are down its less noticable. Any ideas what this may be?

 

It sounds like it comes from the center of the car. The car works perfect right now but the noise is there more so when you first start driving and the car is cool and seems to be almost gone after you've been driving for awhile. Someone else from this fourm told me it may be a transfer case bearing and I should have the transmission checked. It's not very loud if you put down the windows you can't hear it from outside . If you turn on the radio you can't hear it but it's there. It's only when you're not pressing the excelerator and driving slow. When you are excelerating it's gone. I really like this car but am kind of worried about what it may be.