Power steering gear box

I'm sorry I have to start a new thread but I really would appreciate the help, I'm installing a remanufactured pump and cant figure out what this is for. Its a acdelco part on rock auto its 36G055. The part I'm wondering is right below the pcv I'm thinking it might be a fill plug? I tried calling ac delcos tech line and I've searched on the web a few times I hope someone on here might be able to tell me. Thank you for your time