Youngbossray

So i have the w209 5.5Amg, im trying to figure out where this loud grind is coming from on hard acceleration inside the cabin it seems to be directly under the arm rest turns on when i floor throttle makes the noise in a sequence of two such as (clank, clank) followed by slight vibrations ive replaced both flex disc as well as center support could it possibly be balancing the driveshaft or maybe i need a new one or what im kinda stuck here any one else ever run into this problem on any model ???

JoeJErnst

Have you checked your motor mounts? They are a very common failure item and problems show up under hard acceleration when they are bad. Also take a peek at the transmission tail mount to see if it's collapsed.