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| Illustration 1 | g06328921 |
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(1) Hoist control
(2) Service center enclosure (3) Hydraulic oil cooler (4) Hoist cylinders (5) Gear pump (Hoist) (6) Body Position Sensor (7) Oil filters (Hoist) (8) Pressure reducing valve (9) Control valve (Hoist) (10) Hydraulic tank | |
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| Illustration 2 | g03733692 |
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(11) Breather (Pump Drive)
(12) Gear pump (Pump Drive Lubrication) (13) Pump drive (14) Oil filter (Pump Drive) | |
The hydraulic system is electronically controlled through the "Chassis Electronic Control" Module (ECM). A tandem section gear-type pump that is driven by the pump drive provides pressurized oil for the hydraulic system. The hydraulic system is primarily used to raise and lower the dump bed. A four position hoist control lever determines the operation of the dump body. The Pulse Width Modulated (PWM) sensor sends duty cycle input signals to the Chassis ECM. Depending on the position of the sensor and the corresponding duty cycle, one of the two solenoids on the hoist control valve is energized. The four positions of the hoist lever are RAISE, HOLD, FLOAT, and LOWER. The sensor provides a duty cycle signal that changes for all positions of the hoist lever. The duty cycle signal allows the operator to modulate the speed of the hoist cylinders. The hydraulic gauges and other hydraulic components are located in the service center enclosure.