TM-9-2320-285-10
TRUCK TRACTOR, YARD TYPE, 43,500 LB GVW, DED, 4X2, ARMY MODEL M878A1
TECHNICAL MANUAL; OPERATOR’S MANUAL
JUNE 1985
TM-9-2320-285-10 - Page 20 of 121
TM 9-2320-285-10
1-19.
FIFTH WHEEL HYDRAULIC SYSTEM (Continued)
Fifth Wheel Consists of boom and platform.
Two hydraulic cylinders, one mounted on each side of fifth wheel boom,
control raising or lowering of boom.
When hydraulic oil flows to cylinders from hydraulic control valve, piston in each
cylinder will either extend to raise boom or retract to lower boom depending on position of hydraulic control valve spool.
(Positioning of spool is determined by 5th WHEEL lever position.)
Hydraulic Filters - Two filters, one located on suction side, other located on return side, filter hydraulic oil.
Bleed Valve - Provides for manually lowering elevated fifth wheel, returns hydraulic fluid to reservoir.
1-20.
WINTERIZATION SYSTEM
Winterization System Cable - Normally stored in tool box; connects 110 Vac power to junction box at front bumper of
tractor, powering heaters for batteries, engine oil, and coolant.
1-15/(1-16 blank)
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