Service Manual

Rev. D
Groundsmaster 4500--D/4700--DHydraulic System (Rev. A) Page 4 -- 22
Troubleshooting
The charts that follow contain information to assist in
troubleshooting. There may possibly be more than one
cause for a machine malfunction.
Refer to the Testing section of this Chapter for precau-
tions and specific test procedures.
Problem Possible Cause
Hydraulic system operates hot. Engine RPM is too low.
Hydraulic reservoir oil level is low.
Hydraulic oil is contaminated or the wrong type.
Brakes are engaged or sticking.
Piston pump by--pass valve is open or damaged.
Cooling system is not operating properly.
Charge pressure is low.
Traction circuit pressure is incorrect.
Pump(s) or motor(s) are damaged.
Hydraulic oil in reservoir foams. Hydraulic reservoir oil level is low.
Wrong type of oil is in the hydraulic system.
Air is leaking in suction line.
Machine operates in one direction
only.
Traction control linkage is faulty.
System charge check valve and/or system relief valve is defective.
Pilot direction valve in 4WD manifold is damaged or sticking.
Traction pedal is sluggish. Traction control linkage is stuck or binding.
Piston pump servo control valve is damaged.
Charge pressure is low.
Traction power is lost or unit will not
operate in either direction.
Brakes are engaged or sticking.
Traction control linkage is damaged or disconnected.
Hydraulic reservoir oil level is low.
Piston pump by--pass valve is open or damaged.
Charge pressure is low.
System charge check valve and/or system relief valve is defective.
Traction circuit pressure is low.
Front wheel motor couplers are damaged.