I am working on rebuilding the engine of my '97 T509. Long story short, a few years ago the oil pump failed, so I decided to make it a project. I began disassembling it a while back and am finally getting into putting it back together. This brings me to my question.
Part #10 in this diagram:
Do I need it? I don't recall it being in there when I took it apart and it doesn't show up in any of the pictures I took during the process. Also, the top of my new oil pump isn't threaded to accept it. So, I'm convinced it is unnecessary, but I wanted to consult the experts before I put it back together.