C4 part identification

Hello, I am a in process of rebuilding my first C4 '72 tranny. I have a problem with identification of location of one small piece which pulls out during my tear down process. It looks like small valve tip and felt to floor when removing valve body from the case. Please can you help me identify what it's used for and its location in the tranny ? Haynes manual do not said much about valve body assembly and I do now want to assemble back wrongly. Thanks a lot for any idea.