Abstract: The after-running gearwheel of a transmission is engaged by a idler gear mounted for axial movement and rotation. The idler has a conical surface that engages a complementary surface formed on a countercone, which is mounted within the bore of the idler on a common fixed shaft. The shift mechanism moves the idler and countercone forward on the shaft into engagement with the rotating gearwheel. The countercone upon being driven by friction at the mating cone surfaces is fixed against rotation, thereby developing a braking torque that operates to stop the idler and gearwheel. Upon further axial movement, the idler is brought into engagement with the gearwheel on the output shaft.