The study is focused on improvisation on performance of the rear axle of heavy vehicles such as trucks, tractors, trailers, buses and other heavy vehicles subjected to loading more than designed load carrying capacity. Primary objective is to reduce the weight of the entire axle assembly so as to increase the efficiency of the system and reduce the material cost of the axle assembly. Since the vehicles are subjected to loading more than the designated capacity, secondary objective is to improve the stress distribution as a result of excessive loading and effective measures to increase the weight carrying capacity. The base design solid model is subjected to real loading conditions for steady state static analysis. Post analysis the model is subjected to topology optimisation simulation; the results of which are referred for determination of critical area, methods and possible modifications in the geometry and areas where addition or removal of material will optimise the design. Multiple modification in geometry and material assignment has brought up a lighter, efficient, stronger and cost effective model for the rear axle of a heavy vehicle.