Yeah, the pic you have is indeed the EPC Relief Valve, I would show you where it goes but I don't have any pics of the vb. You shouldn't use that anyway according to Jerry, because if that valve gets stuck open then it will cause a line pressure leak which will fail the trans. You will have to get a new vb if you choose not to install it again, because there are 2 holes drilled thru the passages inside that allow fluid to cross over into the passage which has the valve in it. I had one in my trans, you have to put the spring over the plunger's nipple, put the nipple thru the hole in the bracket, and put a paper clip thru the hole in the nipple to retain it until you bolt it into the valve body. Get it? Sorry about not having pics, I could explain it alot better then. The purpose of the valve is supposedly to relieve extreme line pressure due to electrical malfunctions, stuck EPC solenoid, etc.
You will see a hole in the bottom plate of the valve body, about 3/16" or so. The rod's cone end is held in this hole by the spring and bracket. The bracket uses 2 of the vb's mounting bolts. The hole in the rod is for a piece of wire to keep the bracket, spring and rod together while you bolt the bracket in place. Remove the wire once in place.
IMO, I would do something to permanently block the hole, and toss the relief valve parts. Remember that there might be up to 300 PSI behind that hole (not sure, but that's the max line pressure plus some.)