Whirlpool Washer No Spin or Drain

The washer will not spin (in rinse) or drain out the water. All else appears to work. If operated it adds more water and it does agitate. Timer makes its buzzing noise during Rinse/Drain and eventually runs to a stop but pointer never actually reaches off. Tampering with the timer knob in the Rinse/Drain zone never starts the spin. I rarely work on washers. Do you have a suggestion for what part to replace?