1984 marked the year J I Case Company introduced the new 94 Series Agricultural Tractors. With this introduction, a new model tractor was added to the line-up, the 400 horsepower Case 4994. The tractor utilizes a 12-speed, full-power shift transmission, a transmission which required an advanced method of shift control. Technical advances made possible the use of a microprocessor to control not only the transmission of this tractor, but the steering system as well. The following paper demonstrates how this microprocessor has been incorporated into controlling these important functions, as well as displaying many basic self-diagnostic functions to the operator.