Abstract: The response of a transmission shaft in gear transmission system subjected to accidental impact by the joggled gear is simplified as that of a fully clamped beam stuck by an equivalent mass with an initial velocity, which is analyzed within the framework of rigid-plastic method. The effect of torsion is catered for in the Von Mises yield condition and that the strain rate effect is taken into account using Cowper-Symonds empirical constitutive equation. It is found that both the displacement and the rotation are relatively large and that the strain rate effect cannot be neglected. It is also found that the diameter of shaft is a crucial factor in the bending response.