That is the sound (Clunking / Rattle), it only happens when you going slow over something uneven, or a bump. Ford Engineers are refusing to even look at it due to the other ST's on the lot making the same sound. We took the car back from the dealer, however going to keep the work order open for right now. More people need to complain about this issue to your dealer, so Ford will acknowledge that there is a problem. What bothers me is that they are stating that this is a normal sound, but nobody can tell me why it is normal, or where it is coming from. A load of BS from Ford, and their Engineers.