No, you can't see a thing from the top, other than part of the shaft.
If the lever is going all the way "in", and "out", then the problem is likely the PTO clutch halves being worn. The edges of the "clutch" are supposed to be sort of sharp edged, which helps the two halves stay engaged with each other. If they wear (and they do over time), where the edges get more rounded, then they won't stay engaged with each other and it "slips"-making kind of a rattling noise in the process.
Have also seen where the front half of the PTO clutch is jammed hard against the spring and into the splines, thus stuck...but usually this results in NO PTO operation at all. Have also seen a shaft or two broken, but again, usually no operation of PTO. USUALLY. Had one last year that the shaft was broken, but the two halves of the shaft were broken irregularly such that they'd kind of hold against each other enough to turn the PTO shaft, but wouldn't transfer much torque before they'd slip against each other.
pretty easy repair. Split the tractor between the differential housing and the HST case. Your problem should be staring you in the face once it's apart. If it's got a loader on it, you may have to remove the subframes depending on the loader, which is the hardest part, IMO. That and the front wheel drive propeller shaft.