1952, the company acquired Laplant-Choate, which added various models of scrapers to its construction equipment line. In 1953, the WD-45 was introduced, replacing the WD. The motor was increased to 226 cubic inches, giving it 30 horsepower on the drawbar at the Nebraska Tests. This was almost double the horsepower of the WD. A new Allis chalmers designed Snap- Coupler hitch was used. It allowed the operator to hook up to an implement from the seat of the tractor. A Buda diesel-powered WD-45 was introduced in 1955. This series stayed in production until the unveiling of the D-series in 1957. In 1955, the company acquired Gleaner Manufacturing Company, which was an important move for its combine harvester business. Allis was the market leader in pull-type (tractor-drawn) combines, with its All-Crop Harvester line. But acquiring Gleaner meant that it would now also be a leader in self-propelled machines, and it would own two of the leading brands in combines. The Gleaner line augmented (and later superseded) the All-Crop Harvester line, and for several years Gleaner's profits made up nearly all of Allis-Chalmers' profit. Gleaners continued to be manufactured at the same factory, in Independence, Missouri, after the acquisition. In 1957, the Allis-Chalmers D Series of tractors was introduced. It enjoyed great success over the next decade. In 1959, Allis-Chalmers acquired the French company Vendeuvre. Also in 1959, it acquired Tractomotive Corporation of Deerfield, Illinois, which it had been partnering with as an auxiliary equipment supplier for at least a decade. In Haycraft's history of the construction equipment business (2000), he expressed the view that Allis-Chalmers relied too heavily for too long on partnering with auxiliary equipment suppliers, and acquiring them, instead of investing in in-house product development. In his view, this strategy limited the company's success in this business, and it eventually had to spend the development dollars anyway. Buescher's comments about the Buda acquisition and the need for subsequent improvement of its designs seem to corroborate this view. However, the topic is multivariate and complex; elsewhere in his memoir, Buescher presents a viewpoint in which investing in research and product development is an expensive move that often does not pay off for the innovator and mostly benefits competitor clones. 1960s and 1970s In 1960, the U.S. government uncovered an attempt to form a cartel in the heavy electric equipment industry. It charged 13 companies, including the largest in the industry