edip997

I have a 2010 e350 4matic with 94,000 miles on it. Recently I’ve noticed a noise that seems to come from in front of dash in the engine compartment. It is vehicle speed related not engine speed related. The noise is most noticeable with the windows up from the interior, not very noticeable from outside the vehicle or with the windows down. From idle to about 20mph there is no noise, from 20mph to highway speeds the noise increases. No noticeable vibrations, car shifts smoothly, no power loss and drives perfectly.

edip997

Sorry for the short clip. Here’s another.

reefguy

i have a similiar problem as well, the noise frequency is little different, it happens around 35-50mph and kinda goes away in 70-80mph range.. in the beginning changed out the diff. oil no change, i changed the prop shaft support bearing and it seemed to helped, but the noise came back. So im planning to replace
the rear differential, seems the noise is coming from the pinion bearing, and resonating down the prop shaft to the front..

S. Madman

You have a supercharger.

All jokes aside, does it do it with the A/C off?

MBNUT1

OP stated not engine speed related.

Does the noise change with driveline load? If not is likely not the rear differential. If it is not driveline load related it could be the transfer case though that is under the seat not in the front of the car.

dirkdunnit

I had a speed related noise and searched the MB forum with someone suggesting hand/foot rake cable on the prop shaft due to broken plastic clips. I went out and pressed the parking brake pedal hard and the noise stopped.
Next it was up in the air and sure enough broken clips and cable rubbing on a very shiny spot on the prop shaft.
Thankyou MB forum

reefguy

on mines, actually its only in gear 2/3/load. my original thoughts and still, were possibly the clutch packs or bearing/s in the transfer case being the issue.