Patent ID: 8862349

Claim:
A transmission assembly for a powered vehicle, comprising a transmission comprising first gearing and first selectively engageable torque transmitting mechanisms, an auxiliary gearbox coupled to the transmission and comprising second gearing and second selectively engageable torque transmitting mechanisms, a first speed sensor coupled to the transmission and configured to detect a speed of an output of the transmission, a second speed sensor coupled to the auxiliary gearbox and configured to detect a speed of an output of the auxiliary gearbox, and a control unit coupled to the transmission, the control unit having memory, processor circuitry, and executable routines stored in memory to receive electronic signals from the first and second speed sensors, determine whether the transmission needs to be shifted based on the electronic signals from the first and second speed sensors, determine whether the auxiliary gearbox needs to be shifted based on the electronic signals from the first and second speed sensors, and send a shift command to the auxiliary gearbox in response to a determination that the auxiliary gearbox needs to be shifted while the vehicle is in operation, independently of activity of the vehicle operator, wherein the transmission has a number of selectable forward ranges and the auxiliary gearbox has at least one selectable low range and at least one selectable high range, and the control unit prevents any upshift in the transmission when the auxiliary gearbox is in a range other than the high range.