Kenmore Washer Series 90 Intermittent motor problems?

My series 90 (110.28902790) washer sometimes does not aggitate or spin. It happens randomly through different wash cycles. I have replaced the timer thinking it was the problem, but am now thinking it might be the carbon brushes on the motor itself. Any thoughts? I have confirmed it is not the door switch either. During the wash cycle, it might aggitate correctly and spin, but during the rinse cycle it might just sit there when it is supposed to be aggitating etc.. The reverse might happen as well. Any thoughts ? Also, a side note.. Looks like you can't replace brushes on the series 90 motor, might have to buy a complete new motor.. not good.. thx