A convertible transmission system for a vehicle having an input shaft for connection to an engine and an output shaft for delivering rotational power to at least one axle. The transmission has a plurality of available gear ratios resulting in a maximum number of available gear ratios. In addition, a programmable controller is provided for selectively controlling the transmission to operate in a first operating configuration utilizing a first predetermined number of the available gear ratios that is less than the maximum number of available gear ratios. Moreover, the programmable control can have additional transmission configurations by selectively modifying certain operating characteristics, including for example, available gear ratios, desired operating gear ratios, maximum torque limits, shift points, default starting gear ratio, data relating to a predetermined shift strategy, a coast down gear ratio, shift delay timing, and/or skip shifting.