TF-727 Reverse Trouble

The reverse in my transmission decided to take a nap. I never had much of an issue before this matter. I can put it in reverse or neutral with engine off and push it back... With engine running, seems like everything is engaged/shifted forward for the drive position. I can put in reverse/neutral and it just sit there. I pulled the pan and discovered metal in the bottom of the pan. I don't know if a snap ring or what fell victim. All help is greatly appreciated.