Abstract: An improved power takeoff arrangement for a vehicle four-wheel drive transfer case having high, neutral and low positions. The transfer case input shaft has a integral gear member defining the sun gear of a dual planetary gear assembly having its carrier rings grounded to the transfer case housing. A planetary annulus gear, formed with an inboard axial extension concentrically surrounding the inboard carrier ring, is driven by dual planet pinion gear sets journally supported between the carrier rings. The annulus gear inboard extension is formed with external helical gear teeth adapted to mesh with a power takeoff input gear accessible through an aperture in the housing side wall. The arrangement enables power at a constant relative speed to be transferred from the transfer case input shaft to the power takeoff gear in any of its three positions while obviating unbalanced loading of the dual pinion planetary assembly.

Abstract: A dual planetary gear reduction assembly for a two-wheel/four drive vehicle transfer case mechanism providing an exact two-to-one gear reduction ratio during full-time four wheel drive operation. The dual planetary is uniquely designed to provide a grounded carrier supporting inner and outer sets of planetary gears operative to rotate an ungrounded annulus gear and a meshing annulus plate in the same direction as the input shaft. A sun gear, having a predetermined number of helical teeth, is formed on the input shaft while the annulus gear has a predetermined number of internal teeth exactly twice the number of sun gear teeth. A clutch collar is internally splined on the output shaft and has external splines operative, when the collar is shifted into its low-range mode, to engage internal splines on the annulus plate and drive the transfer case output shaft at the two-to-one gear reduction ratio.