The aim is to estimate the dynamic features of the heavy vehicle and their influence on the speed control loop drive. Based on the mathematical description of dynamic processes in hydraulic transmission characteristics of frequency analysis performed dynamic links object of the external drive circuit elektrogidromehanical linear displacements. Set time constants, vibrational frequencies and damping coefficients coefficients inertia control object that has allowed to establish the transfer function in the circuit speed due to hydraulic transmission. To find the explicit form of the characteristic vibration frequencies of the numerator and denominator was assumed the absence of damping properties of hydraulic system that made it possible to set the resonant frequency. Analyzed values of the resonance frequency, which allowed to allocate the reduced transfer function of the external loop over which the outer loop controller setting..