An off-balance dryer drum is rarely a discreet problem. You will hear banging and shaking noises as the drum moves around inside the appliance or the leveling feet cause the appliance to rock back and forth. In extreme cases, the dryer might walk across the floor as a result of the vibrations. The cause of an off-balance drum is often relatively simple to identify and correct.
Take the clothes out of the drum and distribute them evenly around the agitator, if your dryer has an agitator. Loading heavy, saturated items like blankets, duvets and upholstery on one side of a top-loading dryer causes the drum to go off balance while spinning. If possible, wash heavy items with a mix of lighter items like socks, T-shirts and underwear.
Dry large items in a separate cycle. Packing the drum full of clothes may prevent the appliance from starting or cause excessive banging noises as the drum is thrown off balance. One washing machine load equals one dryer load.
Place a spirit level on top of the dryer parallel with the front and one of the sides. The bubble floats in the middle of the vial, between the markings, when the leveling legs are keeping the appliance level. Use an adjustable wrench to turn the leveling legs until the bubble floats correctly in both positions. If the leveling legs are not adjusted properly, the dryer rocks back and forth when thrown off balance.