A gear drive system including a housing having a cavity and first and second opposed, axially aligned output shafts, the first and second output shafts having first and second gears, respectively, mounted thereon. At least one of the first and second output shafts has a predefined range of travel in the longitudinal direction of the first and second output shafts. A gear assembly is in operative engagement with the first and second gears. A spacer is positioned between the housing and one of the first and second gears. The spacer is configured to preclude movement of the at least one of the first and second output shafts through at least substantially all the predefined range of travel. A cover covering the cavity retains the spacer in position between the housing and the one of the first and second gears.