Harnessing the astonishing power of the all-new 2015 WRX demanded an extraordinary transmission.
Subaru met the challenge head-on, developing a new 6-speed manual gearbox.
Source: 15 Model Year Product Information: WRX/WRX STI
Replacing the previous WRX 5-speed manual, the short-throw 6-speed unit features a cable-type shift linkage. Shift throws are short, and the gear lever is easy to operate, providing a truly engaging driving experience.
It’s Anything but Neutral Designed to create a visceral connection to the road, the new 6-speed manual features many new engineering components. Chief among them is a cable-type shift linkage design. In its simplest terms, two cables (rather than rods) connect the shifter to the transmission. One cable is located at the top of the transmission housing, and the other at the side.
The side cable moves the selector arm forward and rearward to change gears. This cable has a counterweight that makes shifting feel more engaging. The top cable moves the selector arm left and right to change gears.
Additionally, the shifter design includes an integrated reverse lockout mechanism. In order to shift into reverse, the driver pulls up the collar that is below the shifter knob and moves the lever to the right (when the transmission is in neutral).
What’s in it for the driver? Compared to a traditional rod mechanism, the utilization of cables provides a quick, responsive shifter feel while transferring less noise to the interior.
Ahead of the Curve The total gear-ratio coverage of all six speeds is wider than the range of the five speeds of the previous WRX transmission. The broader range makes the car more enjoyable to drive from city street to high-speed highway.
By enabling lower engine speeds, the 6-speed also helps to reduce fuel consumption and improve quietness. The gear ratio and shift lever ratio also have been optimized to give the shifter better driving performance and easier gear changes befitting sporty vehicles.
Subaru designed the 6-speed gearbox with overdrive ratios in 4th, 5th, and 6th gears. These gears turn the driveshaft faster than the gears rotate, helping to improve fuel efficiency.
A Smooth Transfer of Power What’s more, the new unit incorporates several performance and durability improvements for high-performance application. In addition to its cable-type linkage, engineers employed synchromesh technology. A synchromesh gear-changing system matches the speed of an intended gear change to the speed of the current selected gear. By matching their speeds, the gear change will be smooth and void of any grinding or noise.
The use of carbon synchronizers for 1st, 2nd, and reverse gears – along with helical gears for reverse – results in smoother gear changes and improved mechanical refinement. It takes less effort to shift. In addition, meticulous honing of both 2nd and 3rd gears for smoother surfaces helps to reduce potential wear.
All Together Every component in the Subaru 6-speed manual transmission is designed and engineered to enhance the driving experience. Besides providing the driver with greater enjoyment and interaction with the vehicle, the transmission is designed for long-term durability, optimized driving performance, and high-level fuel efficiency.