John Deere 6520-6920S Premium

In the fall of 2001, the JD 6020 Premium lineup that was introduced included five six-cylinder models. The smallest, the 110-horsepower 6520, was naturally aspirated; the others were fitted with turbocharging and an intercooler. Rated power on the various models had increased by 5–15 hp, and the maximum horsepower attainable at 250 rpm lower engine speed was 5–8 hp above the rated figures. On the most powerful 6920 S, rated power rose from 150 to 160 hp whenever power was transmitted through the Power Take-Off or vehicle speed exceeded 15 km/h. The engine’s oil change interval was extended to 500 hours when using JD oils, and maintenance costs were otherwise kept low thanks in part to reasonably priced filters.

On the Premium-equipped versions, the PowerQuad Plus transmission featured a four-speed hydraulic powershift. When you changed ranges, the powershift automatically selected the most appropriate gear. An optional AutoQuad 2 package allowed the system to choose the optimal powershift stage based on engine speed and load; two drive programs were available, and the operator could override the automatic system at the push of a button. All six-cylinder models were offered in either 40 km/h or 50 km/h top-speed versions.

At the end of 2003, the AutoQuad 2 was replaced by AutoQuad Plus, which softened gear changes by adjusting engine speed during shifts. A different powershift stage could be preselected for reverse than for forward travel, and the shift-point engine speed could be adjusted in 340 rpm increments. Another option was the EcoShift powertrain, whose gear ratios matched those of the 50 km/h version; on the 40 km/h model, maximum speed was electronically limited and could be reached already at 1,700–1,900 rpm.

Aside from the 6520, there was also a Premium Plus variant that used ZF’s Eccom-based, stepless AutoPowr transmission. Unlike Fendt’s Vario, Eccom combined a four-speed automatic gearbox with a hydrostatic drive, giving the operator the feel of a continuously variable transmission. In contrast to competitors, the accelerator pedal functioned conventionally and could not serve as a speed pedal; travel speed was set by a lever on the armrest control console. The transmission’s behavior could be adjusted steplessly from economical to high-performance. Premium Plus models also came standard with electrically controlled hydraulic valves, though early versions offered only coarse, menu-based adjustment; as of early 2004, flow could be set in 1 % increments.

Lifting capacity was slightly higher than before, and the rear linkage featured a cushioning system to smooth transport driving. The list of optional equipment grew, and the cab received minor updates; measured noise level was 72 dB. Options included headland management (standard on the 6920), automatic climate control, hydraulic front axle suspension, and hydropneumatic cab suspension.

In 2003, a new engine line was introduced with four-valve heads and Denso Common Rail injection; these engines delivered their best torque over a broader rpm range than before, with torque increases of 38–40 %. The 6520’s engine was turbocharged for the first time, and front axles supplied by Dana replaced the previous units.

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