Non Serviceable Motor
The motor bearings might be defective. Most disposers have an opening at the bottom of the housing. Insert either a disposer wrench or a ¼ inch Allen wrench into the bottom of the disposer and wiggle the shredding plate back and forth until it moves freely. If the disposer does not have an opening at the bottom, insert a broom handle into the drain opening and try to wiggle the plate. If the disposer motor still hums after you free the plate, this likely indicates that the motor bearings are defective. The disposer motor is not replaceable—if the disposer motor is defective or worn out, you must replace the entire disposer.