Toro Groundsmaster 4500-D Service Manual page 62

Problem
Cutting units will not raise.
Cutting units raise, but will not stay
up.
Cutting units will not lower.
Hydraulic System (Rev. A)
Possible Causes
Engine RPM is too low.
Hydraulic oil level in reservoir is low.
Lift cylinder(s) is (are) damaged.
Lift arm pivots are binding.
Relief valve for lift/lower circuit is stuck.
Pilot valve in lift/lower manifold is damaged or sticking.
Proportional valve in gear pump is faulty.
Gear pump section for lift/lower circuit (P3) is inefficient.
Lift circuit lines or fittings are leaking.
Detents in lift/lower control valve are worn.
Lift cylinder is damaged.
Lift arm pivots are binding.
Lift cylinder is damaged.
Counterbalance pressure is excessive.
Lift/lower control valve is worn or damaged.
Pilot valve in lift/lower manifold is damaged or sticking.
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