Heavy-duty wheeled tractors need high-performance gearboxes to reliably provide multiple velocities for a wide range of farming operations. Facing the competitive market with ever-changing demands, it is advantageous for manufacturers to develop new gearboxes of high quality within a short development cycle. Based on the Axiomatic Design (AD) Principle, a rapid design system is developed for the generation of complex gearboxes of constant-mesh type exclusive for large wheeled tractors. Supported by a knowledge database and an inference engine, the system is designed to render 3D solid models and output the configurational data of the validated gearboxes that meet the requirements specified by the user. The AD-based gearbox design methodology not only improves the design with higher efficiency and lower cost, it also facilitates further digital manufacturing, which helps agricultural equipment manufacturers streamline product development. The rapid design technology reported herein can be readily applied to other types of gearboxes, such as hydraulic torque converters and planetary gears with the same benefits.