HINGE 5G1259 - Caterpillar

Illustration 1 g01217102
Transmission hydraulic control
(1) Downshift solenoid
(2) Upshift solenoid The solenoids receive an electrical signal from the Power Train Electronic Control Module (Power Train ECM). The solenoids supply hydraulic oil pressure for mechanical work. When upshift solenoid (2) and downshift solenoid (1) are activated, the solenoids allow hydraulic oil to flow to the rotary actuator. The hydraulic oil pressure turns the rotary actuator until upshift solenoid (2) or downshift solenoid (1) stops the hydraulic flow. The Power Train ECM keeps the solenoid activated until the correct signal is received from the transmission gear switch. The rotary actuator is connected to the rotary selector spool. The transmission gear switch is connected to the rotary actuator by a flexible coupling.When the rotary selector spool is in the correct position, the Power Train ECM stops the current flow to the solenoid. The solenoid stops the oil pressure that is going to the rotary actuator. The rotation of the rotary selector spool stops. This sequence occurs for every upshift of the transmission or downshift of the transmission except in NEUTRAL. In the NEUTRAL position, the Power Train ECM will keep downshift solenoid (1) activated after the shift is complete.