Systematic approach in design gives a wide view on product and provides a lot of different concepts. This thesis is a given example of systematic approach in designing of a gear lubricant test rig. The first part of this work and withal of systematic approach is guiding through an explanation of the working principle of devices with closed power loop and study on standardization which, as a result, give constraints on the device and functions which it must achieve. When the task clarification is set, the second phase of this systematic approach can start. In that phase the functional decomposition of the device which present all the functions and their connections are exhibited. Based on that, all technical solutions of partial functions are found and they form a morphological matrix. It provides a wide view on the system and helps to find the new solutions for realization of the final product function. After that, to get the best possible mark in product evaluation, different concepts are set. The product evaluation is done with weighting evaluation criteria. With respect to task clarification, different criteria and their weight are set and according to them, the product has been evaluated. Final product is a combination of different concepts which are set during conceptual phase. After determining of all technical solutions were done, choosing and calculation of the standard components is started. With the chosen standard components, the new constraints on the product are set and they must be fulfilled during calculation and design of non-standard components. All complex calculations are made in software Microsoft Office: Excel and they have been attached as a reference. Simultaneously with calculations, the designing of all the parts was done in software Solidworks. Towards the end, the entire CAD model of the complete device as well as the specific details of the model have been shown.