Volcano EPX Pro: Whining noise then stopped working
 

Hey all:
I replaced the ESC on my redcat volcao EPX pro. A few weeks later the motor would emit a loud whining noise as I ramped up the throttle. Then it just quit. I haven't torn it apart yet. Is the motor fried or the ESC bad? Can I replace the bearings or bushings in the motor? How do I test to see what the issue is?
Thanks for any help!
Matt