Still not giving us a whole lot to work with...
In my mind, metal to metal sound is what you hear when something is very wrong, like a long gone wheel bearing, or a busted leaf spring hitting the frame rails. I suspect yours isn't as severe as either of those so a better description of what exactly you are hearing would help.
Driveway bump, so like you're turning in and hitting the bump with one corner first and then the other, so getting some side to side flex in the suspension/chassis? Or is it any bump, like when you hit a speed bump going straight on?