In 1923, the John Deere Tractor Company introduced a large, standard tractor known as the Model D. The D was the company’s first mass-produced tractor, and it proved so successful that it remained in production until 1953. Over that span of time, many improvements were made to the tractor, including adding a more powerful engine in 1930, a three speed transmission in 1934 and, in 1935, the replacement of steel wheels with rubber tires on most models. The versatile Model D was an all-fuel tractor that could run on gasoline, kerosene or distillate, and it proved durable in the field. Almost 56,000 of them were built, all at the John Deere factory in Waterloo, Iowa. The D was eventually replaced by the Model R, which debuted in 1949. To this day, the Model D holds the distinction as having the longest production run of any single model made by Deere. Dating to the 1930s, this service manual was standard issue for tractor owners. Within its pages you will find discussions of the fuel system, carburetor, water valve, air cleaner, ignition and magneto, cooling system, governor, crankshaft and main bearings, and detailed information about the care and maintenance of the engine and its components from pistons to valves. This reproduction was made using an original copy of the manual. It is presented here as originally published, with care taken to preserve all the original illustrations and text. “John Deere" and the green and yellow paint scheme and other branding elements are trademarks of Deere & Company, all rights reserved.