Debuts on the 2017 Cadenza.

Developed in-house by Kia’s engineers, the new eight-speed automatic gearbox has just about the same size as the company’s six-speed auto but it weighs 7.7 pounds (3.5 kilograms) less. Work on the new transmission kicked off back in 2012 and led to no less than 143 patents registered by the South Korean marque which promises not only a boost in efficiency, but also lower noise, vibration, and harshness (NVH) levels.

Kia already had experience with an eight-speed auto for RWD cars, but engineering an 8AT to cater FWD cars was trickier taking into account it had to be mounted transversely without taking up a lot of space. As such, the size of the oil pump has decreased compared to the six-speed auto and Kia says it’s actually the smallest oil pump developed for a transmission in its class. The company goes on to specify the new unit can use the hydraulic oil in a more efficient way by distributing it evenly at all times throughout the ‘box.

Moreover, the newly developed 8AT has a simplified valve body with only 12 valves (down from 20) thanks to the re-engineered direct control valve body which allows solenoid control of the clutch directly instead of requiring several control valves. As a result of the changes, Kia emphasizes gear shifts are now faster than before and the extra clutch and the two additional gears over the 6AT have enabled a ratio increase of 34 percent between the lowest gear and the highest one. The hardware changes will also pay dividends in terms of fuel economy as well as enable lower NVH levels during acceleration and in higher gears.

The first model to make use of the eight-speed, dual-clutch automatic is the 2017 Cadenza which we drove just last month. Paired with the new biturbo 3.3-liter V6 engine, we found the transmission to be silky smooth up to the point you can barely notice when it changes gears.

The 2017 Cadenza is only just the tip of the iceberg, with Kia saying the 8AT will also be implemented in several midsize and fullsize FWD models in the future.

Source: Kia

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