The piece that you are speaking of is a relief valve, VERY IMPORTANT...if you have "floored it" too many times with out this valve or with it installed incorrectly.....you have toasted the trans..........With a little luck, drop the pan, drop the screen & put the valve into the spring, put the assy up into the valve body with the big head of the valve in first,,, it seals an outlet & the spring holds it in place....
HOW did you put it in & how many floored starts have you tried ? Don't feel bad , a lot of guy's miss this piece completely & fry the tranny on the road test, thinking that flooring it will help........Donnie