Abstract: The speed reducing mechanism employing a planetary gear train can be interposed between a ring (36), engaged with an output gear (13) of the gearbox, and the case (16) which constitutes the input element of the differential. In this speed reducing mechanism, the ring is rotatively guided on two smooth journals and the reducing mechanism can be locked by means of a shifting sleeve (46). Such a simple, small and inexpensive arrangement permits improving the motricity of vehicles having two or four driving wheels, for example of the type capable of travelling over all types of roads and tracks.

Abstract: A gearbox of a front wheel drive vehicle, having a transverse engine, includes a hollow main shaft carrying gears corresponding to different speeds, and has a driving input shaft extending therethrough so as to be rotatable relative to the hollow main shaft, with the driving input shaft having an end gear beyond the end portion of the hollow main shaft. An output shaft in the gearbox has output shaft gears rotatably mounted thereon, with the output shaft gears being permanently engaged with the main shaft gears. Synchronizers fix selected ones of the output shaft gears with the output shaft. A speed reducer is provided, and includes a secondary shaft that is parallel with the hollow main shaft. Two speed reducer gears are rotatably mounted on the secondary shaft and engaged with respective gears of the main shaft gears at different gear ratios corresponding to ranges of different speeds.

Abstract: A rear transmission device of a vehicle with four driven wheels includes a box for transmitting power to the rear wheels, mechanically coupled to a power unit having an axis transverse to the vehicle body, a rear differential and a longitudinal linkage joining the two boxes. The box for transmitting power to the rear wheels is mounted to oscillate about a transverse axis parallel to the axis of the power unit and is joined to the housing of the rear differential by a rigid tube containing a transmission shaft. This assembly is thus integral with and articulated on the power unit. This arrangement constitutes a comparatively simple transmission device which is compact and can be fabricated at a low production cost.

Abstract: This system can be used, in particular, with a vehicle having a transverse drive motor unit and converts a front wheel drive vehicle into a four-wheel drive vehicle. The system includes a central differential driven from an output member of a gear box by means of a hollow body in which the differential associated with the front wheels is housed. The two outputs of the central differential drive the two differentials associated with the front and rear wheels. The arrangement of the differentials is particularly compact and the original housing of the differential can be retained.

Abstract: The transmission device comprises at least two differentials the first of which has two output semi-shafts each of which drives a driving wheel of a first axle of the vehicle. The transmission device includes a second differential interposed between the first differential 1 and one of the wheels of the vehicle, the input element 17 of the second differential 12 being driven by the corresponding output semi-shaft 11 of the first differential 1 and its output elements 21, 23, 24 driving, on one hand, said one of the wheels and, on the other hand, a transmission shaft 32 which is connected to a second axle of the vehicle. The first differential is of the epicyclic gear train type which divides the driving torque applied to its input element in an unequal manner between its output elements.