From what you're describing it sounds something like a coin or key is stuck in one of the drum baffles. Remember to
to the dryer before attempting access.
I recommend removing the top panel in order to access the baffles. Remove the screws securing the baffles to the drum & remove the baffles to inspect for something causing the noise you hear. Other possibilities; drum rollers, belt or idler pulley.
If you do not feel confident repairing this problem yourself, then you can have it repaired at your home by a Sears technician. Here is a link for the website:
Sears Home Services
SAFETY NOTICE: Be sure to disconnect power to the appliance before performing any repairs. If you are not comfortable with doing any voltage checks that might be recommended, please contact your local service provider for repairs. Be aware that there could be sharp edges inside the appliance that could cause cuts or other injuries to yourself or others.