Abstract: The use of production vehicles often takes place at extreme low temperatures which leads to increase in operational costs. Thermal abuse of main units and nodes is caused primarily by the change in viscosity-temperature properties of power fluids. Performance of a suspension hydraulic shock-absorber is tightly connected with viscosity properties of the power fluid. One of the basic criteria of hydraulic shock-absorber performance at subzero temperatures is resistance force. Based on the performed studies, resistance forces of hydraulic shock-absorbers in temperature range from 30°C below zero to 10°C below zero change from 3230-4500 N at rebound with the max allowable value of 4022 N and from 830-1410 N at compression with the max allowable value of 1226 N. The above figures indicate performance deterioration. In this research, we suggest assuring performance of hydraulic shock-absorbers by using a modified shock-absorber fluid. Adding 25 % of diesel fuel by total volume helped to decrease dynamic viscosity of the shock-absorber fluid two times compared to a standard fluid at a given temperature. The use of the designed test fluid will help to increase performance of the suspension and ensure the performance of hydraulic shock-absorbers at subzero temperatures.