A longitudinal plunging unit comprises a profiled sleeve with longitudinally extending first ball grooves, and a profiled journal with longitudinally extending second ball grooves. The profiled journal engages said profiled sleeve with balls arranged in groups in pairs of first ball groove and second ball grooves. A ball cage positioned between the profiled sleeve and the profiled journal fixes the balls in their axial position relative to one another. The ball cage is displaceable relative to the profiled journal between spaced axial stops. On the profiled journal, there is arranged a stop sleeve, which can abut the profiled journal or a component connected thereto. The stop sleeve delimits the displacement path of the ball cage towards the second portion.