An installation for damping vibrations of a drive axle, especially of a rear axle, of motor vehicles, in which the driving pinion of the differential gear which meshingly engages with the spur bevel gear, is driven by way of a universal joint shaft and in which the output from the differential gear onto the axle half-shafts takes place by way of one synchronizing joint each; for purposes of changing the resonant frequency of the system, additional annular parts constructed of shell-shape are clamped onto that part of the synchronizing joint which is connected with the output of the differential gear.