Check out any of the twelve Shift Shaft components enlisted.
On this parts fiche the Nut, U (4kj) is the most specified component.
Parts such as the Shift Shaft: Nut(4py), Shift Pedal Assy, Joint, Rod 2, Cover, Shift Pedal are included in the Tz125 1998 4jt5 Switzerland 284jt-100e1b Shift Shaft parts fiche.