With the purpose to identify the root cause of increased levels of vibration felt at idle speed in a popular vehicle prototype a study was conducted using techniques for analysis of vibration transmission between components of a vehicle, using Mechanical Vibrations Analysis and Operational Modal Analysis, for the analysis of the operational modes was used ODS - Operational Deflection Shape technique which is possible only see the shapes related to probable modes. The experimental results were compared with results for the modal analysis by Finite Element Method (FEM). The vehicles used are identical prototypes, but with different levels of vibration. Therefore, to study there is a vehicle with satisfactory levels and a second with unsatisfactory levels. This study demonstrates the methodology used to identify the cause of the different behaviors between cars and also discuss the improvements made in the body according to the results of the numerical experimental confrontation.