So im doing a filter/flush on the trans and when i dropped the pan, this yellow thing was in the pan when i flipped it over. Im trying to figure out where it goes so i can put it all back together. any help?

 

Nice pix, take that plastic piece and discard it. It was used in the assembly of trans and engine to plug entrance hole and prevent foreign objects from getting into trans. It was more costly to open trans to remove than to push in and let it be removed on filter change. You're in good shape ,can the piece and finish your job. Everybody who sees one of the for the first time almost has heart failure . Have a good day.