whirlpool washer wont fill

back on 12/16/2013 posted original info. screens clean, has power, drum free, only spins once then quits. lid lock functions ok. Fairbanks 56 suggested shift actuator motor. got sick & didn’t get to it till recently. just went to replace the part and found belt almost off small pulley & large pulley loose. how much freeplay on large pulley? would shift actuator cause belt to come off? found tech sheet but washer is apart. can I still test shift actuator at console?

Loose nut on that pulley is a common problem. Take nut off and apply loctite blue 242 threadlocker to the threads and retighten nut.

Eric