Gears are the back bone & one of the most critical components in mechanical power transmission systems.Among the contributors in gear set failure bending and surface strength are identified as one of the contributors which plays major role in it. Thus, to reduce the failure of gear & for optimization of gear design analysis of stresses resulted into major are of interest. In this paper the major focus is on studying stresses and pressure distribution using analytical and finite element analysis for the characteristics of an involute helical gear system. To estimate & identify the various stresses and other important parameters of helical gears, a threedimensional solid model of set of gears is generated using the Computer Aided Design Software Pro/Engineer, which is currently being known as a strong tool for solid modeling. The analytical investigations are carried out by varying the load on gear. This paper also considers the study of contact stresses induced between two gears. To determine the contact stresses between two mating gears, the analysis is carried out on the two gears. A pair of standard helical gears is used and analysis is performed on by FEA Software Altair HYPERWORK OptiStruct solver using the following two conditions for the same power output (i) gear pair made of nylon; and (ii) other pair made of stainless steel. The results obtained from Altair HYPERWORK OptiStuct, are compared to investigate the possibilities of using Nylon as an alternative material for gears against traditional as steel in power and/or motion transmission sector.