The present work deals in performing multi-body dynamic simulation of a truck in ADAMS software. The vehicle vibration levels with respect to the hydro pneumatic suspension spring and the tyre stiffness to be evaluated to find out the sprung mass frequency and the vibration levels were examined. A model of truck is simulated to find the frequency levels of the truck. A 12-ton vehicle is modelled in Pro/E and simulated in ADAMS software to find the natural frequency and the response of the vehicle. The simulated vehicle is tested with the various road terrain inputs and the results were studied.