look underneith. at the back of the pto power divider there is a rubber boot that the hydo pump pto shaft comes out of. Check the condition of the rubber boot. I hear it is very exspensive to change (I think over $1000, but not positive). I also think that changing the boot is alot cheaper if you have a two piece pto shaft that goes from the power divider to the hydro pump.
So if the boot is bad and you have a two piece shaft, probably OK. If its a one piece shaft you are gonna have to do some more research before you buy.
while your underneath check all the pto shafts and universal joints and pillow blocks so you don't run into suprise repairs after you buy.
the rear pto probably won't engage unless the engine is running.
before testing the rear pto check and see that the rear winch is turned off. the control levers are right next to the winch. The levers get bumped and can start reversing as soon as you engage the pto.
take lots of pictures and post them so we can see.