CAMSHAFT AS 3640470 - Caterpillar

Illustration 1 g00905339
Transmission Hydraulic Control
(1) Downshift solenoid
(2) Upshift solenoid The solenoids receive an electric signal from the Power Train/Chassis Electronic Control Module (Power Train/Chassis ECM). The solenoids supply hydraulic oil pressure for mechanical work. When downshift solenoid (1) and upshift solenoid (2) are activated, the solenoids allow hydraulic oil to flow to the rotary actuator. The hydraulic oil pressure turns the rotary actuator until downshift solenoid (1) or upshift solenoid (2) stops the hydraulic flow. The Power Train/Chassis ECM keeps the solenoid activated until the correct signal is received from the transmission gear position sensor. The rotary actuator is connected to the rotary selector spool. The transmission gear position sensor is connected to the rotary actuator by a flexible coupling.When the rotary selector spool is in the correct position, the Power Train/Chassis 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 or downshift of the transmission except in NEUTRAL. In the NEUTRAL position, the Power Train/Chassis ECM will keep downshift solenoid (1) activated after the shift is complete.