It's best to run the diagnostics and do proper testing on this machine before changing parts. F-51 can show up for more than one reason. Also check saved error codes. Click on ApplianceDigest.com in the bottom left of this page and download the Whirlpool Cabrio service manual for all the information you need on this washer Oh by the way, your model washer shows the Rotor Position Sensor as part #W10178988. That is the new style.