A machine has a power train including a prime mover connected to a transmission having two or more selectable gear settings, and a user interface providing an operator selection of at least two gear identifiers of a whole number. Each whole number gear identifiers corresponds to high idle speeds for respective gear settings. The user interface provides a signal indicative of selected gear identifier to an electronic controller, which also receives and transmits signals indicative of machine parameters. The electronic controller contains computer executable instructions which determine an optimal gear setting and whether a gear shift should be made.