How can I add a gearbox block to joint of a manipulator

I ve modelled 2 dof planar manipulator that have two revolute joints in simmechanics. In real system, torque needed for the base joint obtained by a geared dc motor. I m trying to compare real system and simulation but when i apply a torque to the simulation model it continue to rotate a little while real system not because of gear constraint. I think i need to add a gear block to the simulation to take accurate angle data from simmechanics model.