HYDRAULIC PUMP

TM 5-2420-222-20-1

HYDRAULIC SYSTEM - CONTINUED

HYDRAULIC PUMP

Variable displacement, constant pressure pump with eight radially arranged pistons.

Inlet fed by hydraulic oil filter relief valve and speed gear assembly (reverser) clutch control valve through low

pressure oil lines.

High pressure output hydraulic fluid routed through high pressure oil lines to pressure control valve, hydraulic

accumulator, and steering valve.

Passes excess low pressure hydraulic fluid directly to hydraulic oil cooler through low pressure oil line.

Excess hydraulic fluid from hydraulic pump shaft lubrication is routed to transmission case sump through drain line

to protect pump shaft seal from pressure build-up.

Delivers on demand to maintain hydraulic system pressure for operation of all hydraulic system components.

HYDRAULIC PUMP STROKE CONTROL SOLENOID VALVE

Considered part of electrical system.

Normally closed solenoid is opened when starter switch is closed to bypass hydraulic pump discharge oil into pump

crankcase during engine cranking.

Reduces load on engine to make starting easier.

HYDRAULIC PUMP-TO-SPEED GEAR ASSEMBLY (REVERSER) SEAL DRAIN LINE

Routes excess hydraulic fluid from hydraulic pump shaft lubrication to transmission case sump.

Protects hydraulic pump shaft seal from pressure build-up.

HYDRAULIC PUMP-TO-HYDRAULIC OIL COOLER OIL LINE

Routes low pressure hydraulic fluid not needed by hydraulic pump directly to hydraulic oil cooler.

HYDRAULIC OIL COOLER

Considered part of transmission system.

Finned core air cools hydraulic fluid routed to it through low pressure oil line from hydraulic pump.

Routes cooled hydraulic fluid through low pressure oil line to clutch control valve.

HYDRAULIC OIL COOLER-TO-CLUTCH CONTROL VALVE OIL LINE

Routes cooled low pressure hydraulic fluid from hydraulic oil cooler to speed gear assembly (reverser) clutch

control valve.

HYDRAULIC PUMP-TO-PRESSURE CONTROL VALVE OIL LINE

Routes high pressure hydraulic fluid from hydraulic pump, to hydraulic pump pressure line tee-to-hydraulic

accumulator oil line, and pressure control valve.

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