The engine, transmission, and differential oil cooling system keeps the oil clean and within proper operating
temperature range. The components of the system and their fictions are:
Engine, transmission, and differential oil cooler unit is mounted on the engine. By circulating the hot oil
through this unit, heat is given off to the surrounding engine coolant. Engine coolant is in turn cooled by the
engine cooling system.
Oil cleanliness is maintained by circulating engine oil through the engine oil filter, and differential oil through
the differential oil filter. Transmission oil is cleaned by the transmission oil filter which is an integral part of
Differential oil pump is mounted on the transfer gearcase. It pumps oil from the bottom of the differential
housing and to the differential oil filter. Oil flows through the filter, cooler, and back to the top of the
Diesel fuel is stored in the fuel tank located inside the carrier. Fuel is gravity fed to the primary fuel filter. The
engine driven fuel pump draws fuel from the primary fuel filter and pumps fuel through the secondary fuel
filter to the engine injectors. The injectors force fuel into combustion cylinders where it is mixed with air and
changed into energy. The excess fuel is returned to the fuel tank.
External fuel tanks are mounted on rear of carrier and hold about 95 gallons of diesel fuel. Shutoff cocks are
located inside of earner at each connection. Turn fuel on and off for maintenance (M981 only).
The transfer gearcase transfers power from the engine to the transmission. The transfer gearcase is a
compact unit that transfers power from the engine flywheel to transmission torque converter. An engine
disconnect allows the engine to run without transferring power to the transmission. A power takeoff drives the
differential oil pump and a ramp pump. Another power takeoff drives the cooling fan, and a third drives the