That sounds about right but I think it is 10mm. LOL If that is tight, and is turning in the gear box, well, it looks like it may be time for a new one. Or you could just tear it apart and put some sort of spacers in it so it is "pulled up" all the time. It is not hard to switch out. Just a pain to get to the bolts. I recommend taking the time to remove the front body. Makes a world of difference.