Abstract: An electronic autoshift control is provided for a transmission and engine to help reduce demands on the operator. Part of the autoshift feature is an auto/manual switch which is a two-position rocker switch controlled by the operator. The switch determines whether the transmission is being operated in the manual or the automatic mode. In the manual mode, all shifting is performed by the operator by moving the shift lever. Once in the automatic mode, the transmission controller takes over with the autoshift feature. When switched to the automatic mode, an auto/manual lamp is lit indicating the transmission's automatic mode of operation. The rocker switch also functions as a hold switch. If traction conditions are poor and the operator wants to stay in the present gear, the rocker switch can be toggled to the manual mode. This locks the transmission in its present gear and causes the auto/manual lamp to flash if the shift lever selection and the present transmission selection do not coincide.

Abstract: A method is provided for controlling overspeed conditions of an electronically controlled transmission and engine wherein the transmission has an output shaft and is electronically shiftable by an electronic shift control module between forward and reverse gears to rotate the output shaft in forward and reverse directions and a neutral gear without shaft rotation. The transmission has an operator controlled shift lever for requesting a gear from the forward, neutral and reverse gears and operates in a present gear from among the forward, reverse and neutral gears. The method includes determining forced downshift shift points, overspeed downshift shift points, overspeed upshift shift points, a directional shift inhibit speed, and overspeed values for each gear based on transmission speed; determining output shaft speed; and operating the shift lever to request a gear.

Abstract: A traction control for a machine calculates percent slip for the wheels and controls operation the differential lock and the throttle control. It turns both the differential lock and throttle control off when percent slip is less than a slip minimum value, turns the differential lock on and the throttle control off when percent slip is equal to or greater than the slip minimum value and equal to or less than a slip maximum value, and turns both the differential lock and throttle control on when percent slip is greater than the slip maximum value.

Abstract: A torque control lever override of an all wheel drive system matches the front wheel fluid flow, as the wheels are turning, to the flow the pump is generating before the two are connected together. The torque control lever normally controls the pressure and therefore the rim pull delivered to the front wheels. The pump will supply fluid based upon the aggressiveness of the torque control lever which may not always match the current wheel speed. The torque control lever override enhances operation of an all wheel drive system and eliminates excessive harshness when engaging or disengaging the all wheel drive system.

Abstract: A method and apparatus for transmission shift control and prevention is provided. When the inching pedal is not depressed, the transmission is free to shift to the desired gear. When the inching pedal is depressed, the transmission is free to shift to the desired gear if the shift is a shift from a gear into neutral. With the inching pedal depressed and the shift lever moved from neutral into a gear, the transmission is free to shift if the transmission speed is below first gear high idle. When a directional shift has been requested, the transmission is free to shift to the desired gear if the transmission speed is below first gear high idle.

Abstract: Dynamic braking on the all wheel drive front wheel motors of a motor grader is implemented by turning on all the wheel drive system, depressing the inching pedal, sensing brake pressure, determining ground speed, determining a pump set point current using the ground speed, and setting actual pump current to 90% of set point current. Both sides of the drive loop are monitored and the high side pressure is used to control loop pressure. Motor displacement which is normally controlled by shift lever position is set to low displacement for braking. When the all wheel drive system is turned off, the inching pedal is released, or there is a loss of brake pressure the all wheel drive system disengages. The pump upstrokes to provide an anti-lock feature when the desired brake pressure is less than 30% of the set point. The pump upstrokes to reduce pressure and thereby limit maximum pressure when the desired brake pressure exceeds 30,000 kPa.

Abstract: A method is provided for controlling hop in an all wheel drive machine having a torque control lever and a pump for supplying pressurized fluid to wheel motors for effecting all wheel drive. The method includes monitoring machine speed and motor pressure, sensing a first motor pressure fluctuation and subsequent motor pressure fluctuations indicative of a hop, determining desired pump pressure based upon machine speed, and overriding the torque control lever and holding pump pressure constant at desired pump pressure for a preselected time in response to detecting a predetermined number of hops occurring at a predetermined frequency.