I had the rattle from the rear too. Thanks to the group here I was able to isolate it to the rear seat, and the dealership did this to make it go away!

 

That is about all they will do, and more than they did for me. But look at the bright side the noise is gone...

If this "genuine" MB fix doesn’t work too well try the method that I posted on page 2 of this thread to quiet the latch. My fix worked for me from when I posted on Sept 12, 2011 until MB bought the ML back from me in Dec 2012. So for 15 months from when I placed a piece of cloth in and between the latch and seat-back clamp the noise was gone.

The only time the noise came back was when the MB district rep removed it because he didn’t believe me when I told him what I did to fix the noise. The look on his face was priceless when we drove with and without the cloth in place…

 

Hi, just want to share this information for those of you that have problems with squeeking noise from cargo area. Following applies for airmatic suspension.
I finally found out that it was the upper joint in the shockabsorbes that was causing the noise. The easyfix is to drill a 2mm hole (just as deep as you get through the cover, around 2mm) near the upper edge, then spray some 5.56, WD40 or similar into the joint. After spraying, seal the hole.
This can be done without removing the shocks, and is an easy DIY.
My ML is now completely silent again!

Mike