Solenoid Valve (Upshift, Downshift, or Lockup)
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Solenoid Valve (Upshift, Downshift, or Lockup) | |
Upshift and Downshift Solenoids
The upshift and downshift solenoids are outputs of the ECM. The upshift solenoid connects to the ECM at connector contact J2-3. The downshift solenoid connects to the ECM at connector contact J1-12. The upshift solenoid and the downshift solenoid are used to shift the transmission. When the ECM decides to shift, the corresponding solenoid is activated with +battery voltage until the shift occurs. The upshift solenoid and the downshift solenoid control the flow of oil that turns the rotary actuator. The rotary actuator is in the transmission hydraulic control system. Movement (turning) of the rotary actuator shifts the transmission. The upshift solenoid and the downshift solenoid are on the transmission hydraulic controls at the top of the transmission.
The lockup solenoid is an output of the ECM. The lockup solenoid connects to contact J1-59. The lockup solenoid electrically controls the direct drive function. The ECM activates the lockup solenoid with +battery voltage and the lockup solenoid is deactivated when +battery voltage is not present. The lockup solenoid controls the flow of the oil to the lockup clutch valve. Direct drive is used in the upper transmission speeds. The lockup solenoid is activated when the machine is in direct drive. Torque converter drive is used in the lower transmission speeds. The lockup solenoid is deactivated when the machine is using torque converter drive. The lockup solenoid is located next to the downshift solenoid.
Secondary Steering Right-Hand and Left-Hand Solenoids
The left and right secondary steer solenoids are a backup to the primary steer system. If a failure occurs in the primary steer system, the secondary steer solenoid function just like the primary steer solenoids. The "Transmission" ECM outputs to the steering valve control, the secondary steering solenoids, and the secondary steering supply on/off solenoid. The "Transmission" ECM receives inputs from the "Steering Valve Position" sensor based on the position of the valve spool.
When the key start switch is in the on position, the "Transmission" ECM turns on the "Secondary Steering Pilot Supply" on/off solenoid. This action results in pilot pressure being passed through the "Secondary Steering Solenoid Valves".