Whirlpool Duet won't spin, drain pump running

Whirlpool front load Duet washer, model WFW9151YW00, won't spin. Pump was replaced. Control board replaced. Pressure switch replaced. Nothing changed. No error code shows when it gets to spin cycle, just keeps trying to pump. Pump sounds like it's pushing water back and forth, or cycling for about 5 minutes during spin cycle, then machine stops and door unlocks...end of wash cycle. So the machine fills fine, washes fine, drains fine until it gets to needing to spin and the pump just keeps trying to pump what seems to be a small amount of water left but never gets to any significant spin, sometimes I get a few turns but that's it. In diagnostic mode with nothing in the washer it spins briefly and then stops. There is what appears a F3 E2 error code in the history that comes up during diagnostic mode but that error code is apparently linked to the temperature. Thinking to replace motor that comes with the motor control unit attached but getting tired of replacing parts. Any ideas? Can it be a balance issue? Shocks seem OK. Is there an out of balance sensor on these? I couldn't find one. It doesn't appear to knock or bang when running although hard to tell since it won't spin with any clothing in it except for a few slow turns.
Thanks for any help with this. Really would like to figure it out.

via Whirlpool Duet won't spin, drain pump running
by CFix