General Introduction - New Holland T8010 Manual

Section 35 - Hydraulic Systems, 3PT - Chapter 2

GENERAL INTRODUCTION

The tractor uses three hydraulic pumps which are driven through a drive housing on the right side of the range
transmission. The pump drive housing gears are driven by the PTO driveline and all the pumps turn at
approximately 1.33 times engine speed. A PFC piston pump is attached to the front of the pump drive housing
while the tandem gear pumps are attached to the rear of the pump drive housing.
The front section of the tandem gear pump is used to supply the regulated pressure circuit: brake valve,
transmission control valves, PTO and differential lock valve, auxiliary and hitch valve pilot circuits. The rear section
supplies charge flow to the PFC pumps. The PFC pump supplies flow to the priority valve which directs flow to the
steering system, remote auxiliary valves and, the three point hitch.
All hydraulic lines are equipped with O-ring face seals to ensure reliable, vibration resistant connections.
Hydraulic Pumps
Charge/Lubrication Pump
The charge/lubrication pump is the rear section of the dual gear pump and it is used to supply the main PFC pump
with a charged inlet condition to prevent cavitation. The pump also supplies lubrication and cooling requirements
for the transmission.
The pump draws oil from the transmission housing through a 100 mesh suction screen. The pump flow is directed
across the main filter assembly to provide clean charge and lubrication oil.
The pump flow rate at rated speed 2667 RPM (2000 RPM engine speed) is 177 L/min (47 US GPM).
Regulated Circuit Pump
The regulated circuit pump is the front section of the tandem gear pump. The pump draws oil from the system
reservoir through a 100 mesh suction screen. The pump flow passes through the regulated circuit filter housing
and into the priority regulator valve. The priority regulator valve maintains the regulated pressure circuit at 22.4 to
24.5 bar (325 to 355 PSI). The regulated pump flow supplies the PTO/ differential lock valve, transmission control
valves and brake valve. Both the remote and hitch valves are also supplied with regulated pressure.
Once these circuits are satisfied the excess regulated pump flow is directed through the oil coolers and joins up
with the charge pump flow at the downstream side of the main filter head.
The pump flow rate at rated speed 2667 RPM (2000 engine RPM) is 102 L/min (27 GPM).
PFC Piston Pump
The axial piston pump has a variable flow output and can operate at variable pressures. The pump matches the
hydraulic power output to the actual load requirements to ensure maximum efficiency and the minimum use of fuel.
The pump inlet is charged to prevent cavitation. The pump output flow is supplied to the priority regulator valve. The
priority regulator valve gives top priority to the steering system and trailer brake circuit. Once the steering system
and trailer brake circuits are satisfied the priority regulator valve supplies pump flow to the remote auxiliary valves
and three point hitch valve.
The maximum pump flow rate for the standard pump at rated speed 2667 RPM (2000 engine speed) is 146 L/min
(38.6 GPM).
35-2-3