Can someone name this part please?

[GT-ARR]

Can someone help me with the name of this 300zx gearbox part?
I know its a gearbox valve for when is warm the valve trips for the oil cool the gearbox. I think the objective is that.But dont know the name of it need one of this.Asked Nissan for diagram with car chassi number and the part dont appear on there, very weird. Not every version of 300zx z32 have this part.

http://imgur.com/Qc75CZv
http://imgur.com/Q5yrUNw

[GT-ARR]

Can anyone help gonna take the opportunity the car is on "jack" for try to repair this but i don't know where i can find this part.