This project focusses on the Noise, Vibration and Harshness (NVH) performance of a two-stage reduction gearbox from an Electric Vehicle (EV). The recent change to electromobility has made this topic a priority for automotive manufacturers. Mainly, due to the absence of ICEs (Internal Combustion Engines) in EVs, there is a lack of masking sound for other components. One of these components is the gearbox, who raise noise audible to the consumer and reduces the quality perception of the vehicle. To improve the NVH characteristics of the gearboxes, the use of simulations tools are needed to predict their performance beforehand, so the best design can be selected. The objective of this project is to analyse and predict the NVH performance of a typical electric gearbox using computer simulations. In order to understand all the parameters that influence the final sound radiation in the EVs gearboxes. To do so, a model was created and a simulation methodology developed. The created model employs the gearbox from the Rimac Concept_One vehicle as the sample unit to simulate. A combination of multi-body and Finite Element (FE) simulations were used as the methodology to simulate the sound generated and radiated by the gearbox. The gear excitations and bearing forces, corresponding to the given torques and velocities, were extracted by multi- body analyses on the subsystem with gears, shafts and bearings. The surface vibration and sound radiation of the gearbox housing were predicted by FE simulations, with the previously obtained bearing forces as excitations. Finally, the simulation results are presented and analysed. To characterise the gearbox noise, waterfall diagrams are created, relating the sound radiation levels with the frequencies and the engine velocities. This work helps to understand the parameters that affect the creation of sound in a gearbox by simplifying the identification of the key features involved in it. Furthermore, through the simulations of gearbox noise, the time to develop a final product can be reduced by minimising the iteration time of improvement Objectius de Desenvolupament Sostenible::11 - Ciutats i Comunitats Sostenibles::11.2 - Per a 2030, proporcionar accés a sistemes de transport segurs, assequibles, accessibles i sostenibles per a totes les persones, i millorar la seguretat viària, en particular mitjançant l’ampliació del transport públic, amb especial atenció a les necessitats de les persones en situació vulnerable, dones, nenes, nens, persones amb discapacitat i persones grans