TUBE 0794999 - Caterpillar

Wheel End Assembly
Wheel End Assembly
(1) Spider. (2) Planetary shaft. (3) Ring gear. (4) Planetary gear. (5) Axle shaft. (6) Wheel hub. (7) Sun gear.The two wheel end assemblies, one for each wheel, provide the final speed reduction and torque increase in the propel system. Each wheel end assembly has the same components.Axle shaft (5) is connected to the no-spin differential by splines at one end. The other end of axle shaft is connected by splines to sun gear (7). Sun gear is engaged with three planetary gears (4). Planetary gears are held inside ring gear (3), and are mounted to spider (1) with planetary shafts (2). Ring gear (3) is secured to the axle, and does not rotate. Spider (1) is secured to wheel hub (6). The rear wheel is mounted to the wheel hub.Power from the differential turns axle shaft (5). The axle shaft turns sun gear (7). Sun gear turns planetary gears (4). Since ring gear (3) is held stationary to the axle, the planetary gears move around the inside of ring gear. The movement of the planetary gears causes spider (1) to turn. The spider turns wheel hub (6) and the attached rear wheel, in the same direction as sun gear (7), but at a slower speed.Each wheel end assembly has its own oil supply. All components get lubrication as the gears move and oil is thrown about (splash lubrication).Shift Valve
Shift Valve
(1) Working port. (2) Cartridge. (3) Inlet port. (4) Coil. (5) Tank port.The shift valve is an electrically-operated two-position solenoid valve. The shift valve is used to shift the displacement of the propel motor, giving the machine a HIGH and a LOW speed range.Inlet port (3) is connected to the shift oil outlet of the tandem pump. Working port (1) is connected to the propel motor. Tank port (5) is connected to a return line leading to the hydraulic oil tank.When the speed range shift switch (on instrument panel) is in LOW, coil (4) is de-energized. Hydraulic oil from the tandem pump enters the shift valve at inlet port (3). This oil is under charge pressure, 1655 to 2140 kPa (250 to 310 psi). Hydraulic oil from port (3) is blocked at cartridge (2). Working port (1) is open to tank port (5), draining shift pressure from propel motor to hydraulic oil tank. This causes propel motor to remain in the normal LOW speed range.When the operator moves the speed range shift switch to HIGH, coil (4) is energized. This moves a spool inside cartridge (2). Hydraulic oil from the tandem pump enters the shift valve at inlet port (3). This oil is routed through cartridge (2), and exits the shift valve at working port (1). Oil is routed from working port to the propel motor, shifting its displacement to create the HIGH speed range.Cooling and Test Manifold
Cooling and Test Manifold in Off Position
(1) Test port X7. (2) Port C. (3) Chamber. (4) Port D. (5) Chamber. (6) Test port X8. (7) Right side