Abstract: A method of assembling a work machine, such as a skid steer loader, includes manufacturing a lower frame assembly with a pair of laterally spaced side rails which extend along the entire length of the lower frame assembly and a pair of spaced engine mounts distanced from the side rails. Then, manufacturing an upper frame assembly with a pair of laterally spaced side members which extend along the entire length of the upper frame assembly. A rear end portion of an engine is then mounted to the pair of engine mounts. The upper frame assembly is then mounted to the lower frame assembly by connecting the respective side members exclusively to the respective side rails to define a main frame assembly. A bumper assembly is then mounted to the main frame assembly through a connection with the lower frame assembly and includes an engine stabilizer. Finally, a front end portion of the engine is then connected to the bumper assembly at the engine stabilizer.