An articulated vehicle suspension system shoulder joint is disclosed. A vehicle includes a plurality of wheel assemblies; a plurality of rotating shoulder joints, each wheel assembly being mounted to a respective one of the shoulder joints and rotatable in a plane by the respective shoulder joint; and a chassis to which the shoulder joints are mounted. The shoulder joint for use in a vehicle suspension system includes a housing to which a wheel assembly may be attached for in-plane rotation; a drive; and a transmission engaged with the housing and the drive to reduce the speed of the drive motor as it drives the housing.