Plastic agitator connection to washers metal drive gear had worn down, likely due to Whirlpool washer's design that has a tendancy to snag all strings and small items. Thanks to APP, had it up and running again in a few days, the repair itself taking about 20mins. The repair also requires a couple of tools/extensions you may or may not have, I would advise watching the full repair video. Replaced lower agitator (WP3951632) and washplate bolt (W10772621) and so far its running great.