Analysis of the reduction gear body tensed and deformed state is a complex one. Moreover, at each of its stages there have been developed and implemented the original methods permitting to improve the process of calculations and to receive more precise information about the prototype system. At the stage of the model geometry development and its further fragmentation to the finite elements, it has been developed semi-automatic method of meshing, which has allowed for the reduction gear body complex geometry to be represented most precisely. It should be noticed that the calculation precision boosting has also been obtained at the expense of the task dimension extension (more than 500-600 thousand finite elements). For the unknown force characteristics used in the further strength calculation to be rated, the kinematical analysis of the reducer mechanism has been carried out. Examination of three variants of reduction gear body (steel, cast-iron and built-up) required using the methods of non-linear elastic-plastic material characteristics modeling. And the developed methods of modeling the screws and other parts of reduction gear body interaction have boosted drastically the precision of findings.