The shock absorber is an essential part of car suspension system. It insures the required passenger comfort as well as the damping of oscillations resulting from road irregularities. This paper deals with the dynamic behavior of a gas charged single tube shock absorber, used in heavy vehicles. The performance of the studied shock absorber is investigated theoretically by deducing a mathematical model describing the system dynamic behavior and developing a simulation program using the MATLAB package. The dynamic behavior of the studied shock absorber is also studied experimentally. A sinusoidal input displacement was applied to the shock absorber. The transient variation of force was measured for different amplitudes and frequencies of input displacement. The transient response to cyclic ramp displacement was also measured. The simulation results showed good agreement with the experimental results, which validates the developed simulation program. The validated simulation program was used to investigate the transient response of the car suspension system. The transient variations of the vertical acceleration, velocity and displacement of the sprung mass were calculated for typical road irregularity. The validated simulation program is applicable to the different cases of vehicle dynamics analysis.