New here, Komatsu D60-P 6 reverse neutral forward is not engaging

hello i have recently bought a Komatsu D60p 6 serial number 28204. Curious on year. but recently the reverse, neutral forward lever is not engaging. Reverse most of the time and now forward as well? can anyone help me with understanding whats going on. Possibly i can fix it or at least tell a mechanic. any info helps thanks

New here, Komatsu D60-P 6 reverse neutral forward is not engaging