INSERT 5370590 - Caterpillar

Illustration 1 g00861591
Priority valve groupThe priority valve group is mounted on the lower right side of the bevel gear case.The priority valve group contains the priority valve, the torque converter inlet relief valve, and the lubrication management valve.
Illustration 2 g00861601
Priority valve (1) Solenoid valve (2) Oil chamber (3) Sleeve (4) Oil passage (5) Inlet passage from oil filter (6) Inlet passage from oil filter (7) Spool assembly (8) Oil chamber (9) Drain (10) Spring (11) Outlet to torque converter and outlet relief valve (12 ) Outlet to pump (D) (13) Sleeve chamberThe priority valve has an on/off solenoid valve (1) .The electronic control module controls the current to solenoid valve (1) .For de-energized mode, solenoid valve (1) is in the OFF position and inlet passage (5) is closed to inlet passage (6) .For the energized mode, the solenoid valve (1) is in the ON position and inlet passage (5) is connected to inlet passage (6) .When solenoid valve (1) is in the OFF position, the oil from inlet passage (5) flows only to outlet passage (12). The oil from outlet passage (12) then flows to pump (D) and through the check valve. The oil from pump (D) and the check valve divides to supply oil to the steering and brake control valve and the transmission control valve. When solenoid valve (1) is in the OFF position, the main relief valve will regulate high pressure at the priority valve under the following conditions:
Engine speed is less than 1485 RPM. (Until the engine speed is greater than 1535 RPM, the priority valve pressure will remain high.)
Oil temperature in the power train sump is less than 40°C (104°F). (The pressure will remain high until the oil temperature in the power train sump is greater than 45°C (113°F).)
Transmission shift of speed in progress
Directional shift in progressWhen solenoid valve (1) is in the ON position, the oil pressure at the priority valve is regulated by the torque converter outlet relief valve. The oil goes from inlet passage (5) to oil passage (4). Oil from inlet passage (4) flows through a hole in spool assembly (7). Oil then flows through the poppet hole into sleeve chamber (13) and oil chamber (2) .Oil flow to sleeve chamber (13) and oil chamber (2) moves spool assembly (7) to the right against the force of spring (10). This allows oil flow from inlet passage (5) to outlet passage (11) to the torque converter.Braking Operation
The brakes are spring applied and hydraulically released. The service brake pedal and the parking brake switch tell the ECM the braking requests of the operator. The left brake solenoid and the right brake solenoid on the brake control valve are de-energized. When the solenoid valves are de-energized, the brake control valve closes. The pressure for power train oil is not available in order to release the brake. The brakes are fully engaged. When no braking is requested, both brake solenoid valves are energized and the brakes are hydraulically released. The brakes assist in the function