That's some planetary stuff from down in. That plastic piece is the lube dam and the splined shaft you have goes into the 3rd gear sprag.
I have 2-3 transmissions laying around and those parts should be good, or ebay, maybe a trans shop. Likely though, most shops won't stock them because they are standard hard parts that typically don't go bad.
What when wrong with them?
Those parts were not from my trans. they were just based on info from my research of symptoms the car has. I just authorized a full rebuild happening in a couple of days. Let the fun begin.......