CYLINDER AS 0R1807 - Caterpillar

Valve Ports
Illustration 3 g01336456
Bottom View of Modulating Valve (Transmission)
(5) To sump
(7) Charge pressure oil
(8) To transmission clutch Illustration 3 shows the bottom view of the modulating valve (transmission). The bottom view shows the porting for the inlet and outlet flow of hydraulic oil.Valve Operation
There are three basic stages of the controlled operation of the modulating valve:
No signal current
Partial signal current
Maximum signal currentThe operation of the modulating valve is not a simple on/off cycle. The transmission ECM varies the strength of the signal current through a programmed cycle in order to control the movement of the proportional solenoid valve spool.No Signal Current (Clutch Disengaged)
Illustration 4 g01336785
Modulating Valve (Transmission)
(1) Modulating valve (transmission)
(2) Test port
(4) Spring
(5) Line to sump
(6) Spool orifice
(7) Charge pressure oil
(8) To transmission clutch
(9) Solenoid
(10) Ball
(11) Valve spool
(12) Drain orifice
(13) Pin The transmission ECM controls the rate of oil flow through modulating valve (1) by changing the strength of the signal current to solenoid (9). When signal current is not being sent to the solenoid, the solenoid will be de-energized.Oil Flow in a De-energized Valve
Spring (4) holds the