TUBE ASSEM. 7G9927 - Caterpillar

Illustration 1 g01449690
Hydraulic schematic for the axle oil cooler pumps (1) Thermal bypass valve (2) Return line for the steering pilot oil (3) Filter (4) Test ports (5) Filter (6) Thermal bypass valve (7) Front axle (8) Axle oil cooler (9) Axle oil cooler pump and motor (10) Case drain (11) Solenoid valve (12) Manifold (13) Diverter valve (14) Sequence valve (15) Rear axle
Illustration 2 g01450052
(13) Axle oil coolerThe axle oil cooler pump and motor (9) is fastened to the left side of the frame in front of the rear axle. The pump that is connected to the motor toward the rear axle (15) pumps oil to the rear axle housing. The pump that is connected on the rear axle and mounted toward the front axle (7) pumps oil to the front axle housing. The motor that drives the tandem pump is driven by the flow of the steering pilot pump.Each gear pump circulates sump oil from the front axle and the rear axle through an oil cooler. Axle oil cooler (13) is located in front of the radiator. See Illustration 2 for reference. The hydraulic oil circuit helps keep the axle housings and internal brake components cool.The source of the oil for the steering pilot pump that is used to drive the motor of the axle oil cooler pump and motor (9) is the steering hydraulic tank. When the engine is running, steering pilot pump flow enters manifold (11). If either of the following conditions are true, solenoid valve (11) will not energize:
The axle oil temperature of one of the axles is below 30 °C (86 °F).
Machine speed is less than 11 km/h (7 mph) for more than five seconds.When solenoid valve (11) is not energized, steering pilot pump pressure will be sent to the pressure chamber of diverter valve (13). Diverter valve (13) will shift to the left. Diverter valve (13) will divert steering pilot oil flow to the steering pilot system. Diverter valve (13) will cause the oil to bypass the cooling system for the axle oil. Solenoid valve (11) will de-energize when either of the following two conditions are true:
Axle oil temperature for both axles exceeds 35 °C (95 °F).
Machine speed is greater than 13 km/h (8 mph) for more than five seconds and the temperature of the axle oil exceeds 23 °C (73 °F) in either axle.When solenoid valve (11) is de-energized, drain pressure in the pressure chamber for diverter valve (13) will be drained to the tank. The bias spring will shift diverter valve (13) to the right. This will cause diverter valve (13) to send steering pilot pump oil to the motor of the axle oil cooler pump and motor (9) .Each pump in the motor and tandem pump unit (9) sends the axle oil through filter (5) for the front axle and filter (3) for the rear axle. The filtered oil will then flow to thermal bypass valve (6) for the front axle and thermal bypass valve (1) for the rear axle.