Solenoid Valves (Transmission Clutch)
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| Illustration 1 | g00994965 |
Identification of solenoid valves (1) Solenoid valve for clutch 3 (2) Solenoid valve for clutch 4 (3) Solenoid valve for clutch 5 (4) Solenoid valve for clutch 1 (5) Solenoid valve for clutch 2 (6) Solenoid valve for clutch 6 | |
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| Illustration 2 | g01043471 |
Solenoid valve (transmission clutch) | |
The solenoid valves are outputs of the Power Train Electronic Control Module (ECM). The purpose of the solenoid valve is to direct pilot oil to the ends of the control spool. The control spool will move. This allows pressure oil to flow to the corresponding clutches. The Power Train ECM energizes the appropriate solenoid valve for the required clutches for the speed and for the direction that has been selected.
Solenoids (4) and (5) are for direction. Solenoids (1), (2), (3) and (6) are for speed.
In order for the machine to move, one speed solenoid and one direction solenoid must be energized. When the transmission is in neutral, solenoid valve (1) is energized. When the transmission is in neutral, solenoid valves (2), (3), (4), (5) and (6) are de-energized.
The solenoid valves have a connector with two contacts. Connector contact 1 receives power from the corresponding connector contact of the Power Train ECM (J1-11, J1-17, J2-1, J2-2, J2-7 and J2-8). Connector contact 2 of all the solenoid valves join together. These wires return power to connector contact J2-3 of the Power Train ECM.
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| Illustration 3 | g00515287 |
Pulse and hold chart | |
The solenoid valves use a pulse and hold strategy to extend the life of the coil of the solenoid valves. The Power Train ECM has the capability of controlling the amount of current from the output. For ON/OFF type solenoids, the current needed to engage a solenoid is higher than the current needed to hold the solenoid engaged. The pulse and hold strategy makes use of this characteristic of a solenoid by setting the current to the solenoid to maximum and then reducing the current to a lower level after one second. Lowering the current to the valve reduces the heat that is dissipated by the coil of the solenoid.
Note: The solenoid coils are not designed for direct 24 DCV operation. The Power Train ECM sends a 24 volt PWM signal at a duty cycle which provides an average voltage of about 8 to 12 volts to the solenoid coils. Do NOT activate the coils with 24 DCV (+battery) or the life of the coils will be drastically reduced. If the coils must be activated by means other than the ECM, use a 12 DCV source.
Note: The Power Train ECM momentarily prevents the energizing of solenoid valve (1), as the operator shifts from forward direction to reverse direction or shifts from reverse direction to forward direction. Energizing of the solenoid is delayed for two seconds when the operator selects neutral. During this delay, the transmission is in a "no clutch neutral" state. All of the solenoid valves are de-energized during the "no clutch neutral" state. This "no clutch neutral" state is provided in order to improve the quality of directional shifts.
Parking Brake Solenoid Valves
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| Illustration 4 | g01043479 |
Parking brake solenoid valve | |
The parking brake solenoid valves are outputs of the Power Train Electronic Control Module (ECM). The Power Train ECM energizes the parking brake solenoid valves with approximately +24 DCV. Pressure oil will flow through the parking brake solenoid valves when the parking brake solenoids are energized. The parking brake solenoid valve sends oil pressure to the parking brake section of the wheel brakes.
Each parking brake solenoid has a connector with two contacts. Connector contact 1 of parking brake solenoid 1 receives power from the connector contact J1-10 of the Power Train ECM. Connector contact 2 returns power to connector contact J1-7 of the Power Train ECM. Connector contact 1 of parking brake solenoid 2 receives power from the connector contact J1-4 of the Power Train ECM. Connector contact 2 returns power to connector contact J1-7 of the Power Train ECM. Connector contact 1 of remote control parking brake solenoid 3 receives power from the connector contact J1-12 of the Power Train ECM. Connector contact 2 returns power to connector contact J1-7 of the Power Train ECM
Note: Remote control parking brake solenoid 3 is installed when the machine is equipped with the remote control system.
Ride Control Solenoid Valve
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| Illustration 5 | g00774064 |
Ride control solenoid valve | |
The ride control solenoid valve is attached to the ride control diverter valve.
The ride control system uses one solenoid valve. The solenoid valve is energized to activate the ride control system. The solenoid valve is de-energized to deactivate the ride control system. The ride control solenoid is an output of the Power Train Electronic Control Module (ECM).
The ride control solenoid has a connector with two contacts. Ride control solenoid valve connector contact 1 receives power from the connector contact J1-18 of the Power Train ECM. Ride control connector contact 2 returns power to frame ground.