Abstract: In a synchronizing mechanism for clutches, there are provided between the gear shift sleeve and the synchronizing ring (14,15) stop bodies in the form of dogs (25, 26) which are in contact with the gear shift sleeve (between the teeth 34) in the circumferential direction by form-locking engagement and in the axial direction through spring-loaded stop balls (21) and in the neutral position are spaced from the synchronizing ring by a distance substantially equal to the axial extension of the check faces (32, 33) between the gear shift sleeve and the synchronizing ring. In this manner it is ensured that during shifting the axial force previously exerted through the check faces (32, 33) on the synchronizing ring (for instance 15) is replaced by an axial force which is transmitted by the dog and which prevents the synchronizing ring from coming off the countercone before the form-locking connection between the gear shift sleeve and the clutch body is established.