Kenmore washer fault code f 21

Problem with the drain pump. Clogged, stuck, bad. Open pump body up to see what it looks like, if possible. I can open mine but it is an older Kenmore.

You can look up anything from these: https://dl.dropboxusercontent.com/u/8010163/Whirlpool-Kenmore%20washers.zip
https://dl.dropboxusercontent.com/u/8010163/Understanding%20automatic%20washer.pdf
https://dl.dropboxusercontent.com/u/8010163/Whirlpool_WasherMVWC%2BWTW.pdf
You can also go here to look up codes for any make of appliance: Appliance Fault Codes - AppliancePartsPros.com (http://www.appliancepartspros.com/repair-help/appliance-fault-codes.html#Whirlpool%20Duet%20Front%20Loading%20Ga s%20and%20Electric%20Dryer%20Fault%20Codes)
The books I have supplied have very good diagrams and good, clear explanations. Read the one on understanding how the machine works, first. The rest is easy.