To fix a noisy dryer, check for the common causes of this problem, including a stretched drum belt, worn glides or slides or a malfunctioning dryer motor. The dryer casing must be removed in order to check for any of these problems.
Begin by unplugging the appliance and sliding it far enough away from the wall so the back panel can be accessed. Remove the screws that hold the panel in place with a screwdriver. Once the panel is removed, the drum belt's condition can be evaluated. If the belt looks stretched or worn out, replace it. A worn belt causes the dryer drum to wobble and hit the sides of the appliance as it turns, making a loud banging sound.
The dryer's slides are also responsible for stabilizing the drum as it turns, and worn slides causes the drum to spin unevenly. In order to check the dryer slides, the drum must be removed. In most dryer models, all this requires is removing the top of the dryer case and pulling the drum out.
Remove the top of the dryer by removing the screws that attach the dryer cover to the lint trap. The top can then be pried off and the drum pulled out. Owners should refer to the dryer's manual for instructions on removing and replacing dryer support slides. Owners may also check the condition of the dryer motor once the drum has been removed as it is located near the slides.