That does not sound like the fan belt at all, nor would the WSM help in this situation. It sounds hydraulic. Try useing hyd pressure (raise/lower the 3pt, loader or hold the brakes) while you shut it off. This should at least tell you if its hydraulic.
If you do suspect it to be the fan belt just take the fan belt off and start/stop it.
If you do suspect it to be the fan belt just take the fan belt off and start/stop it.