In 1955, Case introduced a whole series of new tractor models. In the three-digit model numbering system, the first number indicated the appropriate number of plow wings, the middle number indicated the fuel type (0=diesel, 1=gasoline), and the last number indicated the design: 0 was the general-purpose model, 1 was the row-crop model, and 2 was the version with high ground clearance. In the 3-wheel row-crop model, the front wheels were now under the front end instead of at the front.

The 300 models had a 2.6-liter diesel engine manufactured by Continental. The base price included 4+1 gears. For an extra cost, you could get a splitter or a Triple-Range version, which had three ranges. The brakes consisted of two discs. An optional feature was a power take-off independent of the clutch pedal. Approximately the same could also be achieved with the hydraulic hand clutch, included as standard equipment, which allowed starting and shifting gears without using the foot clutch. There was a rather comprehensive instrument panel behind the steering wheel. Starting was done via an ignition key.

The 400 models had Case's own engine. There were eight gears. The power transmission was handled by gears, and the 400 no longer had a hand clutch. The electrical system was 12 volts. The seat was spring-mounted with rubber suspension. The hand clutch was only available as an option. Power steering and a power take-off independent of the clutch pedal were also available.

The first model introduced in the new series was the 500, the successor to the LA model. The 500 was equipped with a 6-cylinder diesel engine. Power steering and a rubber-suspended seat were standard equipment. In the USA, it was a fairly new feature to start the diesel engine with an electric starter instead of an auxiliary engine. As an optional extra, a power take-off that could be engaged with a separate switch was available. The 500 was quite successful, but the 4+1 transmission did not meet expectations. For the year 1957, an updated version called the 600 was introduced, with power increased to 70 horsepower and 6+1 gears.

The color scheme was updated for 1957: the engine hood was yellowish, and the frame was a deeper shade of red.

This is an automated translation. Please report any issues in the translation.