Initially I assumed the motor bearings were getting warm and slowly seizing and causing the loud motor noise. I was wrong. It turns out, the blower fan assembly was the root cause. Before you replace the motor, check the blower wheel for small cracks around the center where the wheel connects to the motor. I had small fractures in the plastic from the center nut that moved outward. They were not large, see through cracks, just minor fractures in the plastic wheel. You would never think these would cause the problem! It turns out, as the machine gets hotter, these cracks must grow or expand and oscillate or something because if I ran the dryer with no heat, I didn't have the problem. I replaced the plastic blower assembly (part comes as center wheel and the housing p/n - AP4368345 for my unit) and it's like new. Very surprised those small fractures would generate so much noise! So, if your machine spins fine, the roller wheels are fine etc, but makes a vibrating noise after 10 mins of running with heat, consider this to be the culprit. In general, if the dryer spins ok when you run it, the motor is probably good. I learned the hard way (replaced the motor first).