The most common dryer noise is usually a drum support gone bad--the drum support is a wheel or wheels that are generally at the back of the dryer in the left and right corners---the drum that turns around with the clothes rests on these drum supports,it is common in all brand name dryers for these supports to get worn and make a grinding sound.

If your dryer is a WHIRLPOOL--SEARS--KENMORE--KITCHEN AID--OR --ESTATE, the noise is most likely to be the drum support,usually the drum support that is closest to the flame if this is a gas dryer,and the one closest to the heater element,if this is an electric dryer.

Maytag dryers carry a blower wheel on the front shaft of the drive motor,when this blower wheel is worn out it will make a grinding sound and the dryer will take a long time to dry.

frigidaire dryers have a rear center bearing part of the bearing is attached to the rotating drum,this is in the shape of a ball the other half of this bearing kit is attached to the center back of the dryer frame, the ball is mounted into the cup,whenever the cup is worn the ball will touch the metal that supports the cup,this will make a grinding sound when the drum rotates. 

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