GE washing machine fills, agitates, drains, but does not spin

I have a GE WBSR3140D0WW top loading washer that has stopped spinning. This happened a few weeks ago after I replaced the hub seal to fix a leak. Now it fills, agitates, drains (all fine) but doesn't spin.

I tested the (two contact) lid switch with a multimeter — seems fine.

I tried to test the motor via this video by splicing an extension cord into the motor wiring to sequentially test agitation and spinning.. but neither worked when I did it, even though the unit agitates just fine in a regular cycle. Don't know why it didn't work for me.

I took the tub apart once to replace the hub seal and once later to look around, and don't see anything stuck between the inner and outer tub that might obstruct spinning.

The pressure switch and the place where the tube from it goes into my tub don't appear clogged ( I could blow through them to trip the switch, though I didn't test the switch itself with a multimeter).

I have not really tested other components. I took apart and looked at the timer and didn't see anything visually wrong. I do wonder if there might be something seized or sticking down near the motor/shaft system, but I'm not quite sure how to test that. The belt looks okay, and I can manually turn/rotate it both directions, one way easily, the other way with difficulty and that turns the tub.

Any ideas?

Thanks! Joshua