The article is researching the vibration isolation properties of a flywheel dynamical absorber of the vehicle body oscillations. It is noted that the authors have previously proposed additional flywheel dynamical absorbers with mechanical drives and it is proved that they have improved the vibration isolation properties of the suspension system. However, such dynamical absorbers are heavy. That is why there is being developed a flywheel dynamical absorber with hydraulic drive containing a hydraulic cylinder and a hydraulic machine with a flywheel. The theoretical research identifies the parameters of the hydraulic drive, providing the minimum value of the sprung mass oscillation amplitude in the area of low-frequency resonance, and it is found out that the flywheel dynamical absorber with the hydraulic drive features a lower suspension mass and better vibration isolation properties than the flywheel dynamical absorber with a mechanical transmission.