It turned out to be a small piece of metal about the size and shape of a staple. Went to the junk yard and found an overdrive button assembly in a (Toyota) shifter. I took it apart and it had a staple that was missing on mine. (have no idea where the old one went, but it was small to begin with, so I suppose I’ll never find the 2 broken pieces) I swapped out the staple into the Lexus overdrive assembly, and it worked great.