I recently traded my 2010 E350 4mattic for a 2014. Love the new car but rattling from the rear was driving me nuts. I suspected the rear sunshade since I ha that problem on the 2010 until I got it fixed but while I was investigating the source I inadvertly bumped the comfort box in the trunk and you guessed it, there was the noise. Took the box out and drove down the bumpiest road I could find and it was completely quiet.

I really like the comfort box but not if its going to be that noisy. Anyone had any luck quieting that down?

 

I have the comfort box and it makes absolutely no noise. Make sure the back end is in the holes and the turn screws up front are tight. Also look to see if it is not hitting the sun screen. If the sun screen is to low it will hit the comfort box. Good luck