Power train or an amphibious vehicle having an engine, transmission, and transfer case position in-line with longitudinal vehicle axis towards the rear of the vehicle, with transmission output facing the front of the vehicle. The transfer drive drives the rear wheels via propeller shaft, which extends adjacent the engine to rear differential. A marine drive PTO (power take off) may be taken from a shaft from the transfer case, from the propeller shaft, or from engine crankshaft pulley. Marine drive shaft may run below the engine, or alongside it, on the opposite side of the engine from propeller shaft. Decouplers may be provided to the PTO drive, to at least one rear wheel, and on the optional front axle propeller shaft.