broken plastic ring in turbo AT

I think you can see where it goes in this video: I think its part of the band adjustment

https://youtu.be/llIrDZTxp8w?t=94
Jatco E4N71B Trans Service & OD Solenoid

It is a cool video; thanks for the link, but I don’t think the video explains the plastic ring I found. The ring is not a gasket; at 3.75” OD it is bigger than the overdrive band cover and the overdrive cover gasket is intact, plus, the OD band is outside the pan, and I found these parts in the pan. I think it could be a thrust washer, but I am baffled as to how those two large pieces could have gotten from their original location into the pan without being broken into smaller chunks. So did Nissan use plastic thrust washers in these transmissions, and if so, is it going to work without it?

I think I may have found it: FSM Page AT-25, step #30: Thrust washer.between the inner race and the low and reverse return spring. If it came from there, that might explain how it got into the pan. I'll know more after I get the old filter off. It might be a relatively easy fix. Hahaha. And then I woke up.