COVER 6I6998 - Caterpillar

Axle Oil Cooler
Illustration 1 g03659012
(8) Axle oil cooler pump
(9) Electromagnetic clutch
(10) Relay
(11) Serpentine belt
(12) Heat exchangers
(13) Hydraulic lines to rear axle
(14) Rear axle differential
(15) Hydraulic lines to front axle
(16) Front axle differentialThe axle oil cooler system consists of the following components: Axle oil cooler pump (8), electromagnetic clutch (9), relay (10), heat exchangers (12), and hydraulic lines (13, 15).The axle oil cooler system circulates the axle oil through a heat exchanger and sends the axle oil back to the axle differentials. The heat exchanger uses cooled hydraulic oil to cool the axle oil. The axle oil cooler pump (1) and electromagnetic clutch (2) are located on the engine. The pump is driven by the serpentine belt (11). The temperature sensors (not shown) located in the axle differentials monitor the temperature and report to the Transmission ECM. When the Transmission ECM recognizes an oil temperature of 75° C (167° F), the Transmission ECM sends current to energize the relay (10). When the relay is energized, current is directed to the electromagnetic clutch (9). With the electromagnetic clutch engaged, the axle oil cooler pump (8) draws the warm oil out of the front and rear axle differential (14, 16). The axle flow from the pump is directed through the hoses into the heat exchangers (12). From the exchangers, the axle oil flows to the front differential (16) and to the rear differential (14). If the axle oil temperature drops to 68° C (154° F), the Transmission ECM will de-energize the relay (10).When the axle oil cooling system is activated, the Transmission ECM will also send a signal to the Engine ECM to increase the cooling fan speed. Increasing the cooling fan speed promotes more efficient performance of the axle oil cooling system by providing cooler hydraulic oil to the heat exchangers.