Abstract: A transmission unit for a motor vehicle is provided with a fixed supporting structure, a driving transmission shaft and at least one driven transmission shaft that are parallel to one another, and a control device, which has a control member that is movable with respect to the supporting structure; the control member is able to translate along a control axis between a plurality of operating positions, each associated to a corresponding range of gears, and to turn, in each operating position, about the control axis between an idle angular position and at least one engagement angular position, in which it controls engagement of a gear forming part of the range selected; the control member is set at least in part in front of an axial end of the transmission shafts.

Abstract: A synchronization and engagement device for a gear transmission of a motor vehicle is provided with: a cylindrical hollow portion, which is fixed and coaxial with respect to a shaft of the gear transmission; a toothed driving ring, fixed to an idle or neutral gear of the gear transmission; a first conical friction surface, carried by one between the driving ring and the gear; a floating toothed synchronizing ring, which has a second conical friction surface mating with the first conical surface; and at least one engagement member, which is angularly fixed with respect to the cylindrical hollow portion, is able to slide axially under the action of a control device, and has a cylindrical toothing, designed to render the cylindrical hollow portion angularly fixed with respect to the driving ring. The engagement member is located in a radial position that is more internal with respect to the conical friction surfaces, whilst the cylindrical toothing of the engagement member is an external toothing.

Abstract: A transmission assembly of a motor vehicle is provided with a gearbox having a motion output shaft, whose end 5 carries, in fixed position, a sprocket wheel, coupled to the crown of a differential to transmit motion from the gearbox to the drive wheels; a drive chain or belt transmits motion from the sprocket wheel to the crown, making the output shaft and the crown turn in the same 10 rotation direction; the crown and the sprocket wheel (5) are interchangeable with a toothed crown and a gear directly meshing with the same transmission ratio.

Abstract: A differential assembly, in particular for motor vehicles, transmits the motion from an input shaft to a pair of reciprocally counterposed coaxial output shafts and is provided with a ring gear rotably fed in use by the input shaft about a rotation shaft; the assembly being further provided with a gear set transmitting the motion from the ring gear to the output shafts and having a satellite gear carrier pin, whose axis is orthogonal to the axis of rotation of the ring gear; a single leaf spring is abuttingly coupled to two satellite gears to automatically adjust the position of the satellite gears themselves.