Integrated mounting systems for mounting electric drive components within electrified vehicles may include a cross brace assembly that mounts or supports one or more electric drive components relative to a vehicle frame. A cross brace assembly of the mounting system may include a cross brace, a first bridging side bracket, and a second bridging side bracket. The cross brace may be mounted to lower surfaces of vehicle frame rails and the bridging side brackets may be mounted to upper surfaces of the vehicle frame rails to provide a robust and serviceable mounting solution that evenly distributes vehicle loads.