I think most of us would start with pedal free play. If the clutch is indeed slipping, there probably is none. A slipping clutch doesn't necessarily produce a whine, but who knows?
(If this link works) check and adjust length of rod 080 until you have an inch or so of free play on the pedal and try it again. If it still has problems you might start thinking of splitting it for a clutch.
kpad.kubota.com