I have a shower with a Moen fixture that uses the posi-temp valve (10+ years old). There is a vibration and some odd faucet behavior in that the water pressure is much lower when the shower is running hot than when it is set to be cool or cold. An identical shower in my guest bathroom is fine.
So I bought a replacement valve but am not sure how to install it. Does anyone have details of the process? (The box might be missing instructions).