If you have a washing machine that won't spin or perhaps won't agitate and you have eliminated all other causes, then you will probably need to overhaul your transmission.
In this video, we do a complete overhaul on a Whirlpool direct drive transmission. We cover the agitator cam assembly and the spin gear / neutral drain assembly. After watching this video, you should be able to overhaul your own washing machine's transmission completely.
Check below for links to the parts you'll need and diagrams and schematics you may need.
Neutral Drain Kit:
https://amzn.to/31gUxyq
Whirlpool Agitator shaft complete:
https://amzn.to/3vJOiiG
Agitator Cam Plastic Parts:
https://amzn.to/3QszRrm
Gear Oil:
https://amzn.to/3p2Fi4G
Oil resistant gasket maker:
https://amzn.to/3P1v3Id
Here is a link to the Whirlpool manual that explains the workings of their transmission:
https://applianceassistant.com/ServiceManuals/787930a_l-55_whirlpool_direct_drive_washers.pdf
Direct Drive Transmission Schematic:
https://www.canva.com/design/DAFIrdX0eIQ/dQwRBpVv1HbLNFSXwOyR-A/view?utm_content=DAFIrdX0eIQ&utm_campaign=designshare&utm_medium=link2&utm_source=sharebutton