A technique facilitates control over the orientation of a bottom hole assembly. A planetary gearbox assembly incorporates a sun wheel which cooperates with planet wheels at a plurality of levels along the planetary gear box assembly. The sun wheel and the planet wheels cooperate to convert rotational input to rotational output through an output carrier. Torsional rigidity characteristics of the sun wheel and the output carrier are selected to distribute torque loading across the plurality of levels of the planetary gear box assembly. The distributed forces reduce the potential for component failure.