A mechanical system theoretically should not generate any vibrations and noise to be considered dynamically an ideal system, because vibrations mean a loss of energy. In planetary precessional reducers vibration can appear at bearings, gears, misaligned shafts, unbalanced rotors, couplings. Changes in dynamic process affects not only normal behaviors of mechanical systems but also the forces that act here. Regarding this aspects, regular vibration measurements during the operating speed provide information about any necessary repairs or maintenance. Here vibration research was made by using GUNT PT500 Machinery Diagnostic System and vibration signals was evaluated by using GUNT PT500.04 software which allow to perform correct Fast Fourier Transformation analysis. Data acquisition was made by using two piezoelectric accelerations sensor type IMI603C01 and one reference photoelectric sensor to record the shaft speed. Research concluded in this paper is made on precessional gearbox 2K-H Type. In first phase the crankshaft was installed with self-alignment on 2 radial bearings with cylindrical roller and second research phase was determination of the resonance domain and performing the spectral analysis by recording several vibrogram.