Buzzing Noise at 1350 rpm
 

Hey guys, weird problem, my 2005 E320 CDI emits a buzzing sound at exactly 1350 rpm under very light acceleration or going up a slight incline. Noise goes away immediately at either higher or lower revs or with heavier throttle input or at no throttle. I'm stumped, but here are a few possibilities:

1. Something in the trans
2. Driveshaft center support bearing
3. engine or trans mounts
4. A bearing on one of the belt driven accessories (I don't think this is it because if I rev it in park or neutral there is no noise).
5. Just some weird harmonic quirk of this car
6. ???

Any thoughts or ideas?

Read this for some information:
https://www.benzworld.org/forums/w21...ng-1200-a.html
Mike T.

Thanks, looks very similar to the issue I'm having. I appreciate it!