It sounds to me like the motor might be on its way out. Sometimes the bearing in the motor can go bad over time and the motor will overheat because it isn't rotating freely. If you disconect the belt and spin the motor shaft, it should spin about a revolution before stopping. If it seems like there is resistance and the motor doesn't spin freely, the motor is bad and will need to be replaced. When replacing the motor, sometimes the blower wheel will get stuck and not like to come off without damage to it.
This is the motor and blow wheel for your model dryer:
Drive Motor - 279787 (PD00002347)
Blower Wheel - WP697772 (PD00003053)
