After removing the old pump, I connected 12VDC to test it out. It appeared to spin up, and operate fine. So I took it apart to see what it looked like inside. The impeller looked fine. But underneath the impeller, there appears to be a cup shaped magnet that powers the impeller. That part was fractured, and detached from the motor armature. Some of it was ground up inside the motor housing. I'm pretty sure this is what caused the pump to fail.