Abstract: A transmission includes a multi-speed geartrain comprised of an input shaft, a mainshaft, and a plurality of constant-mesh gearsets arranged for selectively coupling the mainshaft to the input shaft for driven rotation at various speed ratios. The mainshaft can be selectively coupled to the power transfer arrangement for establishing two alternative power transmission routes. In particular, the range shift mechanism is provided for establishing a high-range power transmission route and a low-range power transmission route from the mainshaft to a quill shaft which, in turn, drives the interaxle differential. The torque delivered by the quill shaft is split by the interaxle differential between the front and rear drivelines to establish the full-time four-wheel high-range and low-range drive modes. Optionally, the torque transfer apparatus can be provided for controlling speed differentiation across the interaxle differential or in place of the interaxle differential for on-demand four-wheel drive operation.