By the 1930s, the company expanded in other automobile parts servicing. After an unsuccessful foray into the fertilizer distribution business, the company began to manufacture trailers, the equipment for which required an investment of over $12,000. In 1937, they began manufacturing dual-axle trailers, suitable for on- and off-road use. The new design of trailers was a commercial success and in 1938, the incorporated company Gunderson Bros. was formed, with its factory in Linnton, Portland, Oregon. In 1941, the company began building ships. The company distributed, installed and pioneered the use of General Motors diesel engines.