Fault diagnosis is a mandatory process in modern industry management, because it may reduce costs due to unexpected failures that may occur in machines. It is proposed to study the dynamic effect in the rotor response of gear tooth crack caused by bending stress. As the bearings are the common location to install sensors as accelerometers, the response in their corresponding degrees of freedom is considered. A geared rotor model is assumed for the simulations. This model embraces a detailed finite element discretization, which contemplates five degrees of freedom per node, including torsional rotation. In addition, a time-varying mesh stiffness calculated by the potential energy method is adopted to represent the tooth contact. A crack model is assumed with three input parameters (initial position, propagation angle and depth). A design of experiments was set up to show the influence of each parameter on the system response for three different mean depths. The results analysis pointed out that for a precise parameter identification, all three parameters should be taken into account, because they affect the system response and they also present combined influence.