Selection of proper technological surface layer well resistant to cyclic external loads superposed onto residual stresses is presented in this paper, with a gear wheel taken as an example. The computer simulations of external loads were carried out by means of the FEM method (Finite Element Method) with the use of the ANSYS package. Residual stresses were measured by means of the Waisman-Philips and modified X-ray sin2Ψ method. The results of the stress superposition were verified experimental by with use of a circulating power stand. The applied low pressure nitiriding method NITROVAC demonstrated a high ability to increase the durability and reliability of the discussed toothed wheel in comparison with the convencional treatment applied so far.