My Maytag Performa toploader washer stops moving during wash and rinse cycle.

I watched it fill with water, then the agitator started moving. After a minute or so, the agitator stopped moving but the motor was still running. I moved the knob to the spin cycle and the washer drained and spun as normal. Wonder if there is some sort of belt that may be wearing out? Any suggestions would be appreciated. Merry Christmas!---Rob