The damaged Drive gear teeth are numbered accordingly and schematic view is presented in Fig. 3. It was observed that Drive gear was severely damaged by total lose of approximately 9 teeth and the rest 11 were badly deformed with cracked finned edges at the tips. The surface was contaminated with debris and lubricating oil. The cracks and pitting at the deformed teeth surface occurred due to the cold working of case under higher applied load. The Drive gear teeth (2, 3, 4, 5, 6, 7) were badly worn and severely deformed upto the pitch surface and hardened case was sheared off during sliding of meshing gears as shown in Fig. 4. The addendum of Drive gear was totally lost by the reaction of face surface with Driven gear and