With automakers’ increasing commitment to electrification and the rapid growth of the electric vehicle market, researchers and engineers are focusing on increasing the efficiency of the subassemblies that make up the electric vehicle’s powertrain. Following the trends on developing integrated propulsion systems, that consists of both the electric machine and the transmission into a single subassembly, together with the needs to their higher efficiency, a shared cooling and lubrication system was designed and virtually developed. Knowing its functional strategy and using mathematical approach, its design parameters were determined. The losses for the electric machine and the thermal behavior of the transmission were evaluated. In addition, the calculation and the sizing of the oil cooler and the pipes were achieved. The virtual prototype of the shared cooling and lubrication system and the integrated propulsion system were realized and then virtually integrated onto a L6E vehicle chassis. The complete system was designed with increased levels of modularity and scalability, allowing its use on various vehicle platforms.