The rear corner panels on either side of the tailgate (black plastic) can crack or break. They should be cut off and the adhesive removed before new panels are glued on.
Car Problem Reports
Mercedes-Benz ML500 Rear Corner Panels on Sides of Tailgate May Crack/Break
Mercedes-Benz ML500 Problem
Average Mileage: 71,000 mi (31,000 mi - 135,000 mi)
Visitor, 2004 Mercedes-Benz ML500, 31,000 mi
THE PANELS ACTUALLY STARTED PEELING OFF THE CLEAR COAT AFTER ABOUT A YEAR OF OWNING THE VEHICLE SINCE NEW. I AM CURRENTLY TRYING TO FIGURE HOW TO REMOVE THEM MYSELF AND PAINT THEM.
Visitor, 2002 Mercedes-Benz ML500, 135,000 mi
Side panels have lost the clearcoat and now are flat black. I had same problem on my ML430 and had the dealer install new ones and after a year they did the same thing. I just gonna deal with it.
Visitor, 2003 Mercedes-Benz ML500, 78,000 mi
Both black panels peeled/crack.