Priority And Regulator Valve - New Holland T8010 Manual

Section 35 - Hydraulic Systems, 3PT - Chapter 2

PRIORITY AND REGULATOR VALVE

The Priority/Regulator Valve is located on the top right side of the range transmission. The valve consists of the
following components: priority spool, regulator spool, and steering relief valve.
The front section of the dual gear pump and the PFC piston pump supply oil to the Priority/Regulator Valve in the
following manner:
Priority Spool (Supplied By PFC Piston Pump)
Oil flows into the Priority/Regulator Valve from the left side port (2). Steering has first priority, oil flows across the
priority spool (11) and out the steering supply port (3). There is a cross drilled passage near the top of the priority
spool. Oil enters this orifice and starts to build pressure against the spring. As steering demand is satisfied,
pressure builds on the top of the priority spool (11) and the spool moves down against its spring, opening a
passage to the remote and hitch circuits (13).
When the steering circuit is placed on demand this causes a pressure drop on the top end of the priority spool (11).
Signal and spring pressure work against pump outlet pressure and the priority spool (11) moves up to
accommodate steering demand.
Once steering demand is satisfied, pressure builds on the top of the priority spool (11) and the spool shifts down to
increase flow to the remote and hitch circuits.
When equipped with trailer brakes, oil is also supplied from the priority valve to the trailer brakes.
Regulator Spool (Supplied By Regulated Pump Section)
Regulated pump flow enters the Priority/Regulator valve at the right side port (7). Oil flows across the regulator
spool (12) and supplies all the regulated circuits through the side port (6) and top port (4). The oil also flows
through the orifice near the top of the regulator spool (12). This oil builds pressure and moves the regulator spool
against the spring. This regulates pressure and maintains the 325 to 355 psi (22.4 to 24.5 bar) in the regulated
circuits. These include the transmission control valves, PTO/differential lock valve, brake valve and regulated
pressure for remote valve and the hitch valve pilot pressure.
When all regulated circuit demands are met the regulator spool continues to maintain the 325 to 355 psi (22.4 to
24.5 bar) pressure and allows excess pump flow out the cooler supply port (5).
When a regulated circuit is activated, the regulator spool (12) senses a momentary drop in pressure. The spring
will overcome the spool and move it up to allow for an increase in flow of oil to meet the demand. As the demand is
met, pressure again builds on the top side of the spool through the orifice and moves the spool down to maintain
regulated pressure.
35-2-31