Abstract
In this study we grouped the automotive models in three classes, depending on the provisional reliability level, and there were processed the data gathered for the defect "noise during changing gears" in the warranty period, for a representative lot of each of the three classes. Finally, we obtained the Weibull law estimating the reliability for each class of automotive. We also defined analytically the inverse of Weibull function, and using it we determined for each class of automotive the periodicity of first technical inspection, for an imposed reliability minimum of 95%. This first technical inspection will also include the preventive maintenance activity named "listening the gearbox". We noticed that for the first two classes, with a low provisional reliability, it is necessary to outrun the first technical inspection, and for the superior class the established periodicity is confirmed.
Keywords: reliability modeling, preventive maintenance, technical inspection.