The invention relates to a power train for a motor vehicle, in particular a truck, comprising a hydrodynamic retarder (10) which can be mechanically connected to a driveshaft (1) in a driving manner and disengaged from said driveshaft by means of a disconnect clutch (14). The hydrodynamic retarder (10) is positioned on a speed-boosting shaft (9) in a speed-boosted mode relative to the driveshaft (1), said speed-boosting shaft being connected to the drive shaft (1) via a speed-increasing ratio. The invention is characterized in that the speed-increasing ratio is designed in at least two steps and comprises an intermediate shaft (5) on which the disconnect clutch (14) is positioned. A first gear step (3) is provided between the driveshaft (1) and the intermediate shaft (5), and a second gear step (7) is provided between the intermediate shaft (5) and the speed-boosting shaft (9). The hydrodynamic retarder (10) and the disconnect clutch (14) are positioned either together between the first (3) and the second (7) gear step or together on the first (3) gear step side facing away from the second (7) gear step or together on the second (7) gear step side facing away from the first (3) gear step with respect to the axial direction of the drive shaft (1).