The motor was worn out.

I first leaned the washer up and "walked" the belt off of the motor pulley. Then I lifted the top cover of the washer and propped it up so I had access to the screws in the front cover. I took out the two screws at the top of that cover and lifted it out of the way to get to the motor. I took out the mounting bolts and then removed the ground wires. I followed the lead of a previous "repair story" by taking the electrical wires off the old motor, one by one, and immediately putting them on the new motor in order to get them in the right spot. The only issue I had was that one of the ground-wire screws was smaller than the hole that had been tapped on the new motor. Otherwise it was really simple and the job was finished by completing reassembly in reverse order of disassembly. And the old washer seems to have more life in it today.