Transfer case having selectable driving modes suited to motor vehicle load and road conditions

A motor vehicle powertrain producing multiple-speeds comprising:

• a transmission including an input and an output, the transmission producing multiple ratios of a speed of the input and a speed of the output;
• a transfer case including a second input driveably connected to the transmission output, a second output continually driveably connected to a first set of wheels and releasably connected to a second set of wheels, and a gearset for producing alternately in the transfer case a low speed ratio and a high speed ratio;
• a mode selector for producing a signal representing a desired driving mode;
• and
• a controller, responsive to the signals produced by the mode selector, and accessible to a schedule of transmission speed ratios and transfer case speed ratios that correspond to a desired driving mode, for controlling the transmission to produce alternately the multiple speed ratios of the transmission, and for controlling the transfer case to operate alternately in the low speed ratio and high speed ratio that corresponds to the desired driving mode and a current speed ratio produced by the transmission.