Abstract: A hydraulic transmission device for a machine, including a declutchable hydraulic motor having radial pistons, and including a cam that is secured to a casing, and a cylinder block and an internal fluid distributor that are disposed in the casing; a hydraulic pump including a drive member; and fluid exchange couplings; in which device the casing and the distributor are mounted to rotate relative to a stationary support about an axis of rotation, whereas the cylinder block is fastened to said support. In some embodiments, the drive member of the pump is constrained to rotate with the casing of the motor, and in that a delivery orifice of the pump is connected to one of said couplings.