Synchronizing unit for a motor vehicle transmission, comprising - a guide sleeve which can be fixed co-rotationally to a transmission shaft and has external toothing, - a sliding sleeve which has internal toothing and which, via the internal toothing, engages in the external toothing of the guide sleeve and is mounted such that it can be displaced axially in relation to the guide sleeve, - at least one synchronizing ring (8a, 8b), which is mounted such that it can be displaced axially in relation to the guide sleeve and rotated to a limited extent, - a number of pre-synchronization units (20a, 20b), which act between the sliding sleeve and the synchronizing ring (8a, 8b) in such a way that the synchronizing ring (8a, 8b) can be displaced axially during an axial displacement of the sliding sleeve, wherein the pre-synchronization unit (20a, 20b) has a spring element (23a, 23b), a detent element (22a, 22b) and a synchronizing ring driver element (21a, 21b), and wherein the synchronizing ring driver element (21a, 21b) is attached to the synchronizing ring (8a, 8b) so as to be fixed in the axial direction, and wherein the detent element (22a, 22b) is supported under spring load on a recess (25a, 25b) of the sliding sleeve and is held on the synchronizing ring driver element (21a, 21b) in order to transmit the axial displacement movement, wherein - the synchronizing ring driver element (21a, 21b) is also designed in such a way that in the event of a rotational movement between the guide sleeve and synchronizing ring (8a, 8b), a relative movement between the detent element (22a, 22b) and the synchronizing ring driver element (21a, 21b) is possible, wherein - the detent element (22a, 22b) is a ball, a hemisphere with a square main body or a hemisphere with a cylindrical main body, and the synchronizing ring driver element (21a, 21b) is formed in one piece with the synchronizing ring (8a, 8b), characterized - in that the synchronizing ring driver element (21a, 21b) is designed as a lug extending axially, into which a window-like recess (28a, 28b) for guiding and supporting the detent element (22a, 22b) is introduced, and in that the recess (28a, 28b) has a clear width A in the axial direction which is adapted to support and hold the diameter of the detent element (22a, 22b), such that the latter is held in supported fashion on both sides in the axial direction, and that the clear width B extending in the transverse direction is greater than the diameter of the detent element, so that, during a rotational movement of the synchronizing ring (8a, 8b) in relation to the guide sleeve, the detent element (22a, 22b) is guided so as to slide along the recess in the transverse direction and permits a decoupled relative movement between the detent element (22a, 22b) and the synchronizing ring driver element (21a, 21b). - a guide sleeve which can be fixed co-rotationally to a transmission shaft and has external toothing, - a sliding sleeve which has internal toothing and which, via the internal toothing, engages in the external toothing of the guide sleeve and is mounted such that it can be displaced axially in relation to the guide sleeve, - at least one synchronizing ring (8a, 8b), which is mounted such that it can be displaced axially in relation to the guide sleeve and rotated to a limited extent, - a number of pre-synchronization units (20a, 20b), which act between the sliding sleeve and the synchronizing ring (8a, 8b) in such a way that the synchronizing ring (8a, 8b) can be displaced axially during an axial displacement of the sliding sleeve, wherein the pre-synchronization unit (20a, 20b) has a spring element (23a, 23b), a detent element (22a, 22b) and a synchronizing ring driver element (21a, 21b), and wherein the synchronizing ring driver element (21a, 21b) is attached to the synchronizing ring (8a, 8b) so as to be fixed in the axial direction, and wherein the detent element (22a, 22b) is supported under spring load on a recess (25a, 25b) of the sliding sleeve and is held on the synchronizing ring driver element (21a, 21b) in order to transmit the axial displacement movement, wherein - the synchronizing ring driver element (21a, 21b) is also designed in such a way that in the event of a rotational movement between the guide sleeve and synchronizing ring (8a, 8b), a relative movement between the detent element (22a, 22b) and the synchronizing ring driver element (21a, 21b) is possible, wherein - the detent element (22a, 22b) is a ball, a hemisphere with a square main body or a hemisphere with a cylindrical main body, and the synchronizing ring driver element (21a, 21b) is formed in one piece with the synchronizing ring (8a, 8b), characterized - in that the synchronizing ring driver element (21a, 21b) is designed as a lug extending axially, into which a window-like recess (28a, 28b) for guiding and supporting the detent element (22a, 22b) is introduced, and in that the recess (28a, 28b) has a clear width A in the axial direction which is adapted to support and hold the diameter of the detent element (22a, 22b), such that the latter is held in supported fashion on both sides in the axial direction, and that the clear width B extending in the transverse direction is greater than the diameter of the detent element, so that, during a rotational movement of the synchronizing ring (8a, 8b) in relation to the guide sleeve, the detent element (22a, 22b) is guided so as to slide along the recess in the transverse direction and permits a decoupled relative movement between the detent element (22a, 22b) and the synchronizing ring driver element (21a, 21b).