Mahindra PTO keeps disengaging. 485 d8

[Bowfisher09]

I have a 97 Mahindra 485 di, couple days ago while mowing with bushhog the pto disengaged on its own "lever keeps popping back out" only when idled up into higher rpms suitable for cutting. Never has it done this. I checked hydraulic fluid level, pto shaft has very little in and out play. Any ideas or suggestions? Thrust bearing? Seals? Havent taken the pto cover off yet but probably will soon.

Thanks!