Gear that has been shredded / powdered from a heavy door being lifted over time. This powder that accumulates is serious. Over time the motor will start to not lift like usually does. If you experience a garage door that has lifting issues / closing issues then you make very well have a gear that is become shredded. If you have any garage door lifting / closing issues then you should call us at: 604-890-8918 and we can discuss any garage door repairs that you require.