Kubota L4200DT GST rear pto shaft not working, seeking advice

[Bananaman]

Hello, here's my dilemma and your advice is most welcome.
Kubota L4200DT GST 4wd. Independent pto system (hydraulic), not transmission based pto. Has this ol friend 28 years, not many problems til now
Now this issue is rear pto shaft lost it's mojo, only try to spins but can't. ( there is no mid-pto)
This issue started during last mowing session, and I did hit a big rock. Brushhog mower does has a slip clutch, yet I'm concerned after several years in this rainy place it's clutch has locked up and the damage has gone to the tractor pto system. Here's a vid of the pto shaft behavior. What do you think, internal pto clutch pack, shaft coupling, gear?
will try to upload a vid to show it's behavior.

 

[CubDieselFan]

I know this is not good news but it looks like a gear or something that transmits power to the shaft from the hydro motor is stripped.

 

[MA_Pahn]

I'd start cheap: check the PTO lever cable and the control valve before tearing into the guts. Sometimes the linkage sticks or gets sloppy and you get that weak spin. If fluid looks burnt or low, that's another easy check before blaming gears.