peerless 5 speed shift linkage problem

[trainman 0]

Before I screw anything up since I am a newbie on riding mowers my 211-5 has the 5 speed manual peerless transmission. the shifter lever keeps coming loose where it screws into the top of the transmission I have snugged it up twice and it keeps coming loose, I was thinking of putting lock tight on the screw but wanted to ask on here before I do something wrong. Lastly the metal plate that is held in by four screws that covers access to the shifter lever is that supposed to have like half moons like this in the plate it self ) or should these be ground flat? so you can just slide the shifter to the next gear? :woohoo: