A bi-directional overrunning clutch for controlling torque transmission to shaft segments of a primary drive axle of a wheeled machine, the bi-directional overrunning clutch comprising: a clutch housing adapted to be engaged to and rotated by an input, the clutch housing having an inner cam surface on it; a pair of hubs (32, 34) each adapted to engage an end of a respective shaft segment of a drive axle for rotation therewith, each hub having a plurality of axially-extending recesses on an outer surface; a pair of roller assemblies (44, 46) disposed within the clutch housing, each roller assembly including a set of rollers positioned around at least a portion of one of the hubs, a roll cage (50, 52) having a plurality of slots, each roller being located within a slot, the roll cage being located about at least a portion of the respective hub, the roll cages (50, 52) engaging each other for limited relative rotation such that when one roller assembly is in one of the forward-engagement position and the reverse-engagement position, the other roller assembly cannot move into the opposite direction of the forward-engagement position and the reverse-engagement position, characterised in that each roller assembly further comprises a single spring tending to urge all the rollers radially inwards to seat in respective ones of the recesses in the respective hub; with each roller assembly (44, 46) being located adjacent to the inner cam surface, the inner cam surface adapted to provide wedging engagement of the rollers between the inner cam surface and the respective hub when the roll cage is rotated in a first direction relative to the clutch housing into the forward-engagement position and when the roll cage is rotated in a second direction relative to the clutch housing into the reverse-engagement position, the second direction of rotation being opposite the first, the inner cam surface defining a released position of the rollers between said forward-engagement position and said reverse-engagement position in which radially outward movement of the rollers is permitted against the action of the spring to free the rollers from the recesses in the respective hub to permit relative rotation of the hub and the respective roller assembly. a clutch housing adapted to be engaged to and rotated by an input, the clutch housing having an inner cam surface on it; a pair of hubs (32, 34) each adapted to engage an end of a respective shaft segment of a drive axle for rotation therewith, each hub having a plurality of axially-extending recesses on an outer surface; a pair of roller assemblies (44, 46) disposed within the clutch housing, each roller assembly including a set of rollers positioned around at least a portion of one of the hubs, a roll cage (50, 52) having a plurality of slots, each roller being located within a slot, the roll cage being located about at least a portion of the respective hub, the roll cages (50, 52) engaging each other for limited relative rotation such that when one roller assembly is in one of the forward-engagement position and the reverse-engagement position, the other roller assembly cannot move into the opposite direction of the forward-engagement position and the reverse-engagement position, characterised in that each roller assembly further comprises a single spring tending to urge all the rollers radially inwards to seat in respective ones of the recesses in the respective hub; with each roller assembly (44, 46) being located adjacent to the inner cam surface, the inner cam surface adapted to provide wedging engagement of the rollers between the inner cam surface and the respective hub when the roll cage is rotated in a first direction relative to the clutch housing into the forward-engagement position and when the roll cage is rotated in a second direction relative to the clutch housing into the reverse-engagement position, the second direction of rotation being opposite the first, the inner cam surface defining a released position of the rollers between said forward-engagement position and said reverse-engagement position in which radially outward movement of the rollers is permitted against the action of the spring to free the rollers from the recesses in the respective hub to permit relative rotation of the hub and the respective roller assembly.