In 1957, the first models of Allis-Chalmers' D series were introduced to the market: the D14 and D17. The design was started almost from scratch, and the styling was modern for its time. The driver now sat in front of the rear axle. The front axle track width could be adjusted without a jack. For attaching implements, Allis still offered its own Snap-Coupler quick hitch, but later a standard three-point hitch also became available, allowing the use of the same implements with other brands. Advanced technology included an oil-bath Power-Director hand clutch, which was used to shift ranges, and the neutral position allowed the hydraulics and power take-off to operate while the transmission was in neutral.

The D14 matched the power and size of the previous WD45 model, but instead of the predecessor’s 3.7-liter engine, it had only a 2.4-liter engine. The D17 was equipped with either a 3.7-liter gasoline engine or a 6-cylinder 4.3-liter diesel. Thanks to the high-low gear, it had 8+2 gears.

In 1960, the D15 replaced the D14, with increased engine power achieved through higher RPM and compression ratio. A diesel version was also introduced. At the same time, Allis’s traditional orange color was changed, and a cream color was added alongside it. The model range was broad: gasoline, gas, and diesel versions were available, as well as narrow orchard models, high ground clearance versions, etc.

At the end of 1961, the first turbocharged tractor was introduced: the D19 Diesel. The power increase was modest, but the 38-inch wheels also made the tractor feel larger than the D17.

In 1964, a new hydraulic system was introduced, with relatively low pressures but significantly higher pump output than before.

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