Kohler K-401 thermostatic valve disassembly

[ozark01]

I have a Kohler K-401 shower valve that I am trying to replace the thermostatic valve because it will not turn at all either way.

I have gotten the valve disassembled to a point but now I am not sure how to get the next pieces removed. In the picture you see a plastic cap and a collar with temperatures on it.

Any advice on how to remove the plastic piece and collar would be appreciated. I see no screws so I guess that it either pulls off or screws off but if i keep on I am going to break something.

Thanks!

Update 4/12/2025-

If anyone is interested the gray plastic piece pulls off. It was stuck on the splined shaft of the thermotic valve.

There is not much info on-line about this faucet and Kohler has been not help at all.

Update 4/13/2025
More info if you need it.

Got the thermostatic cartridge out and found that my valve is a K-404-K with 1/.2" connections rather than a K-401-K with 3/4" connections like I originally thought it was. They use different cartridges I discovered. The 404 uses a 1021119 cartridge and the 401 uses a 78913 cartridge. The 78913 cartridge was about $60. The1021119 cartridge is about $200.