New Holland T8010 Manual page 907

Lower Function and Troubleshooting
FUNCTION
Hitch Valve in Lower - To lower the hitch, the lower solenoid (2) must be energized by the Electronic Hitch
Controller based on the commands entered by the operator. Activation of the PFC system is not required to lower
the hitch. When the lower solenoid (2) is energized, the armature will move toward the valve, contacting the control
pin (14), which pushes the lower pilot spool (4) inward. The amount of movement depends on the amount of
current that is sent to the solenoid by the Electronic Hitch Controller based on the commands to the controller by
the operator. As the lower pilot spool (4) shifts, it meters regulated pressure from the regulated pressure supply
(12), through the overload relief, to the lower control piston (7). The piston moves to the right and pulls the lower
pilot poppet (8) off its seat against spring (15) tension. Pressure escapes to tank creating a drop in pressure behind
the lower poppet (9). The pressure in the raise/lower port now moves the lower poppet off the seat. The hitch can
now lower as oil flows through to the tank port.
The hitch will stop lowering when the solenoid (2) is de-energized. Oil pressure acting on the left end of the lower
pilot spool (4) moves the spool outward closing the regulated pressure supply (12) to the lower control piston (7).
As the pressure drops on the piston the pilot poppet (8) returns to its seat by spring force. With the pilot poppet port
closed pressure from the hitch cylinders builds behind the lower poppet (9) through the orifice (16) forcing the
poppet onto its seat trapping oil in the hitch cylinders.
TROUBLESHOOTING
Problem - Hitch will not lower
1. Check the function of other systems (Transmission, Remote valves).
A. If other regulated pressure systems do not operate properly, refer to troubleshooting of non-operating
system.
B. If other systems operate properly, go to Step 2.
2. Check for HITCH fault codes.
A. If fault codes are found, refer to troubleshooting of any fault found.
B. If no fault codes are found, refer to Step 3.
3. Check for manual operation lower function by pushing in on the lower manual operating pin (14) in the center of
the outer end of the lower solenoid with a small punch or 1/8 inch rod.
A. If the hitch lowers, test hitch lower solenoid (2) for proper electrical function and recheck HITCH error
codes.
B. If hitch does not lower, refer to Hydraulic Troubleshooting of the Regulated Pressure System. If the
hydraulic system functions properly, go to Step C.
C. Check the hitch control valve for free movement of the lower pilot spool (4), the lower poppet (9) and the
lower control piston (7). Check condition of all O-ring seals and replace as necessary.
Section 35 - Hydraulic Systems, 3PT - Chapter 9
HITCH CONTROL VALVE
35-9-20