The global transition towards a CO2 emission reduction in the transportation sector forces the OEMs to rethink in a more efficient way how to convert and transmit the energy to produce motion for the vehicles. Recent years have seen an increasingly transition to the electrified vehicles, both hybrid electric vehicles (HEVs) and battery electric vehicles (BEVs). Efficiently planning the widespread adoption of electric vehicles (EVs) relies on accurate energy consumption estimates and the ability to assess drivetrain efficiency. A critical consideration for EVs is the selection between single-speed and multi-speed transmissions, as it significantly affects overall vehicle efficiency. This thesis presents a comprehensive review of recent research and technical progress present in literature related to the evaluation of efficiency and performance of the different types of transmission applications in EVs; the main sources of power losses present in a gearbox, and the methodology used to compute the power losses for the new Dana 2 speed transmission in order to obtain the efficiency maps of the gearbox..