This paper presents a transient vibration analysis of a nonlinear full-vehicle. The full-vehicle model consists of a powertrain, a trimmed body, a drive line, and front and rear suspensions with tires. It is driven by combustion forces and runs on a road surface. By performing time-domain simulation, it is possible to capture nonlinear behavior of a vehicle such as preload due to gravitational force, large deformation, and material nonlinearity which cannot be properly treated in the conventional steady state analysis. In constructing a full-vehicle, validation process is essential. Validation process is applied with respect to the assembling sequence. The validation starts with component levels such as tires, springs, shock absorbers, and a powertrain, and then the full-vehicle model is constructed. Model validation is done in two aspects; one is model accuracy and the other is model efficiency. In the component level, validation is focused more on how to model components accurately, and then the degree of detailed modeling of each component is compromised with model efficiency during assembling components into the full-vehicle, because the feasibility of simulation time becomes more substantial as the model gets complicated. The transient nonlinear full-vehicle simulation is initially applied to idle and wide open throttle (WOT) analysis to verify the validity of the transient nonlinear analysis. And then it is applied to lock-up and impact harshness problems as examples of transient events.