Challenger unveils innovative AutoPower VI transmission providing greater economy, efficiency and ease of operation

The new Challenger AutoPower VI transmission, recently introduced as an additional option on Challenger MT500B Series tractors, is proof that less truly is more. Building on the success and reliability of the proven AutoPower IV, the AutoPower VI is the first transmission to offer six powershift ratios that can be shifted under full load within four mechanical, robotized selected ranges.

Adrian Crisp, general marketing manager for Challenger mid and high horsepower wheel tractors will tell you, " The superb shifting operation of the 24 forward and 24 reverse gears offers a level of flexibility not seen before on any powershift transmission, allowing the operator to shift up and down and select exactly the correct ratio for any field or transport operation."

"The left-hand power control lever is used to select forward/reverse directions and to declutch the transmission, just as it does with the TechStar CVT and AutoPower IV," Crisp explains. "It can also be used to select the autopower ratio, leaving the right hand free for other controls. The real innovations," he insists, "are found on the right side of the cab."

Using a new T-handle control lever, mounted on the armrest console, the operator can now manually change both the autopower ratio and the gearbox range under load, without using the clutch. For autopower ratio changes, the operator simply moves the handle forward or back to pulse shift through the six ranges marked "A" through "F" (autopower ratios can also be changed with the power control lever). To make ranges under load, simply push the range button on the control handle while moving the lever forward or backward.

"The straightforward, simple operation permits an easy progression from minimum to maximum speeds with a minimal amount of driver input," says Crisp. "As a result, the operator can quickly find the perfect balance of engine speed and travel speed for any type of job. In fact, more than nine gears in ranges 2 and 3 fall within the typical field working range."

Easy, clutchless shifting is only one part of the AutoPower VI transmission's talents. The new powertrain also incorporates a rotary-dial autodrive controller that provides automatic shifting in several different modes. Set the dial to "manual" for manual shifting with the back up of overspeed protection. Or turn the dial to "speedmatching" for automatic autopower range selection after a manual range change has been made.

For even more automation, the controller offers two unique "autodrive" sectors. Rotate the dial to the left for "Road" or right for "Field." In each sector, the operator selects the desired engine speed between 1,600 and 2,200 rpm, which, in turn, controls the up-shift and downshift points at which the transmission will automatically select the next ratio. In each case, shifts are automatic in response to both engine speed and load, providing full power and torque control and engine braking.

In the "Field" sector, the transmission will only change the autopower ratio, while the operator makes range selections. In the "Road" sector, the transmission changes both the autopower ratio and the gear range. In essence, driving the tractor on the road is like driving a car with an automatic transmission.

"With six autopower ratios in each gear, there's seldom a need to change ranges in the field, regardless of whether you're running in manual or autodrive mode," says Crisp. "Moreover, maximum speed can be achieved at as little as 1,800 rpm on most models. Depending upon the load, that can translate into improved fuel economy and a reduced noise level."

Naturally, the operator can still pre-select forward and reverse starting gears, as well as the aggressiveness of shuttle clutch modulation. For those who need more gear choices at lower speeds, Challenger MT500B Series tractors also offers a 4:1 creep option, which extends gear choices to 36 forward/36 reverse; or an 8:1 supercreep option, which provides 48 gears in each direction.