The PTO shift lever broke on my Massey 231. I took the old one off and while trying to install the new one I noticed that the pto gear wont slide back and forth (as I believe it should) on the pto shaft to be able to swap from engine speed to neutral to drive speed. I have done everything I know to do to try to make it move. I see no evidence of a keeper or a lock to keep it from sliding freely but it will not move at all. Any advice is greatly appreciated.