Mecanum Wheel not spinning

[Dominick Ferone]

We were running tests with our drive train from last year to test how well the mecanum would go over the bump. While testing the robot seemed to drift towards one side a little every once in a while. Later the wheel had completely stopped spinning. The gearbox is below the c-channel and when we pulled off the gearbox, cleaned out any debris(alot of what looked like steel shaving stuck to the motor.) and tested a new talon and pwm as well it worked well at first but then it stopped spinning again. Does anyone know what may have caused this issue?