I got my motor open tonight. It was very difficult to open by the way. I tried and tried tapping the shaft on a piece of wood and finally I had to put it in a vice put a piece of wood on the shaft and hit a couple times till it popped open. Turns out there was a loose piece of soldier floating around inside the motor. The sand must have knocked it loose.

One thing I noticed when I put the rotor back in the can was that most rotors will pull out of your fingers from the magnetic forces when you try to slide it in. The MM rotor did not pull out of my fingers. It slide in without effort. Now I'm wondering if the motor is somehow demagnatized or is that just the way it's supposed to be?