Abstract: A sliding gear for a speed-changing transmission, idling on an output shaft, has a set of external running teeth in permanent mesh with a driving gear and a set of internal clutch teeth engageable with mating teeth on a coupling member carried by that shaft. The two sets of teeth have centerlines inclined to the axial direction by angles so related as to exert balanced axial forces upon the sliding gear in the engaged position of the latter. The clutch teeth have flanks diverging from their centerlines at small angles, in the direction of the engagement shift, to hold the sliding gear in contact with the coupling member.