My 2009 whirlpool front load washer (WFW9500TW03) squeaks per the linked video when there is a heavy enough (half full?) load in it while rotating.

I'm hoping to find out what the likely root cause is and the complexity and cost of fixing it.

See video here...
https://youtu.be/HSbgdmFchPo

I've looked to see that it might be the drain pump, drum drive pulley, or drive belt...
http://www.********************...9500TW03/Symptoms/Noisy/

I'm thinking it's one of the latter two, but am open to ideas and suggestions here. Just successfully put in a new inlet valve assembly, so I can do some level of repairs on my own.

Thanks!