Abstract: An articulated four-wheel drive tractor has front and rear frame structures joined by vertical pivots and supported by front and rear drive axle assemblies. The tractor has a split, speed change transmission with a first section supported on the front frame structure and a second section supported on the rear frame structure. The first transmission section is driven by an engine mounted above the front axle structure and its output is transferred to the second transmission section through an upper driveshaft which crosses the axis of articulation and drives a gear train on the rear frame structure forwardly of the second transmission section. The second transmission section output shaft is connected directly to the rear axle assembly and is connected to the front axle assembly through a second driveshaft which crosses the axis of articulation below the upper driveshaft.