METHOD FOR SYNCHRONISING AN IDLER GEAR ON A GEARBOX SHAFT

A method for synchronising an idler gear before coupling of same on a secondary shaft of a parallel-shaft gearbox comprising at least one primary shaft connected to a drive source of a vehicle, at least one secondary shaft carrying the idler gear for transmitting the torque from the drive source to the wheels of the vehicle at a transmission ratio, and at least one coupling means for coupling the idler gear to the shaft of same having no mechanical synchronisation members, characterised in that the drive source is controlled, before the coupling, at a speed imposing a differential speed with respect to the synchronisation speed thereof at the transmission ratio which is to be engaged, this differential being determined as a function of the quantity of energy absorbed by the vehicle at the time of coupling in response to the disappearance of the differential.