A lot of times the grinding sound that is heard when going over bumps is actually the car scraping the cement. If it is not a serious problem then the best thing to do would be to drive slow over the bumps.
Bad wheel bearing is one possibility.
The bearings on the alternator could be going bad. Remove the belt from the alternator then spin the alternator by hand to listen for grinding.
sounds to me like a really bad c.v joint or joints
possibly your wheel bearing is on its way out
Usually it'll be a grinding sound.
Something loose or broken. Try to determine if its when going over certain bumps or down straight smooth terrain.
your brakes are about to give out... you should go to wal-mart and have them replace them
Yes, the differential can make a grinding sound.
brake shoes or pads are worn and need replacing
If its a ka thunk sound even on small bumps,Its most likely your STRUT MOUNTS.
I would have the brakes checked ASAP. As to the rattle there maybe a nut that came off something and is inside something and the bump makes it move. The two may not be related.
There is a good chance your rotors have been worn too thin, which in turn causes the crunching/grinding sound when stopping