Abstract: A work vehicle comprising a motor, a drive unit for driving a ground engaging portion, a torque converter for variably transferring power from the motor to the ground engaging portion, a lubrication circuit for providing lubrication fluid to the torque converter, and a control valve located between the torque converter and the lubrication circuit. The work vehicle further having a linkage for performing a work function, an actuator to controllably move the linkage, a sensor coupled to the actuator to sense a force opposing the actuator, and a controller in communication with the sensor and the control valve. The controller is adapted to command a crowd reduction in response to the sensed force opposing the linkage, whereby the pressure of the lubrication fluid provided to the torque converter is reduced.

Abstract: An articulated four wheel drive work vehicle is provided with a front axle having a front differential and a rear axle having a rear differential. Both differentials are provided with hydraulically operated differential locks that are coupled to respective solenoid control valves. The solenoid control valves are coupled to a microprocessor. The microprocessor has a manual mode in which the differential locks are controlled by a foot pedal in the operators cab and an automatic mode in which the microprocessor controls the differential locks in response to speed signals from the axles and the transmission. The microprocessor calculates a predicted axle speed based on the transmission output speed signal received by a transmission speed sensor. The microprocessor then compares this signal to the actual axle speed signals received from axle speed sensors and triggers the respective solenoid valve if the difference is greater than a programmed amount.