HOSE AS 3078782 - Caterpillar

Fourth (Direct Drive)
When the transmission control is moved to the FOURTH position, the rotor for the shift lever switch is moved to the FOURTH position. With the shift lever switch in this position, current flows from the EPTC II through the shift lever switch to machine ground.EPTC II determines that FOURTH gear is needed. The rotary selector spool turns the rotor on the transmission gear switch as the transmission shifts through the gears. As the rotary selector spool turns, the rotor on the transmission gear switch is turned by a flexible coupling. When the rotor on the transmission gear switch is in the FOURTH position, current flows from the EPTC II through the transmission gear switch to machine ground. EPTC II determines that the shift is complete. The machine is now in FOURTH gear and the machine is in direct drive.Shifting Procedures
The following sections will explain the operations of automatic upshifts and downshifts. Except for different electrical wires that must be grounded or activated, the shifting sequence is basically identical for all speeds.Typical Automatic Upshift (SECOND to THIRD)
When the transmission control is put in THIRD speed position, the rotor for the shift lever switch is turned to the THIRD speed position. Current goes from the EPTC II through the shift lever switch to machine ground. This current flow and a signal from the transmission speed sensor will inform the EPTC II that an upshift is needed. The upshift to THIRD speed position from SECOND speed position is automatic when the correct ground speed signal from the transmission speed sensor is sent to the EPTC II, and the transmission control is in THIRD speed position or above THIRD speed position.The EPTC II stops current flow to the lockup clutch solenoid when a shift is necessary. The lockup clutch solenoid deactivates. Hydraulic oil to the lockup clutch stops and the machine is in torque converter drive for a moment. At the same time, EPTC II sends a signal to the Engine ECM. The Engine ECM will decrease the engine speed during the upshift.EPTC II sends current through the upshift solenoid to ground. When the upshift solenoid activates, hydraulic oil pressure goes to the rotary actuator which turns the rotary selector spool. The rotary selector spool turns the rotor on the transmission gear switch. When the alignment of the rotor on the transmission gear switch changes from SECOND speed position to THIRD speed position, current from the EPTC II will go through the transmission gear switch to ground. This new current flow tells EPTC II that the transmission is now in THIRD speed position.EPTC II deactivates the upshift solenoid when the transmission gear switch and the ground speed is in the operating range for THIRD speed. EPTC II will then activate the lockup clutch solenoid. The lockup clutch solenoid will send hydraulic oil pressure to the lockup clutch. At the same time, EPTC II signals the Engine ECM to increase engine speed. The machine is now in direct drive THIRD speed.Special