Design & Technology

Independently developed 6-speed automatic transmission April 27th, 2009

Seong-hoon Park

By Seong-hoon Park, Senior Research Engineer
Automatic Transmission Design Team

Hello Kia BUZZ readers!
My name is Park, Seong-hoon and I’m a senior research engineer at Kia and part of the Automatic Transmission Design Team that developed the automatic transmission for Kia’s existing new line of vehicles.

Let’s talk about the development of our newest transmission and its significance for our cars.

The front-wheel drive 6-speed automatic transmission delivers high fuel efficiency and low CO2 emissions. Kia is one of only three global automakers in the world to develop the transmission as part of a strategy to secure and lead core technologies suitable for a sustainable future.

Oil prices have prompted consumers to regard fuel economy as an important consideration when buying a car along with the need for responsible, eco-friendly purchase decisions.

Early on, we recognized the need to secure transmission technology. Since we are localizing those related technologies, we managed to develop our own 4-speed and 5-speed transmissions.

Continued efforts in R&D led to the in-house development of a 6-speed automatic transmission. This feat has not only enhanced our brand image but will produce hundreds of billions of won in savings every year by eliminating the need for reliance on outside technology. We have also secured the latest cutting-edge technology for automatic transmissions.

What are the major features?

The biggest feature on the front-wheel drive 6-speed automatic transmission is a completely unique layout for which we secured 300 patents during the development process. We joined an elite class of automakers (following Toyota and a GM/Ford joint venture) who have this proprietary technology which improves fuel economy/performance and shift quality versus the previous generation’s 5-speed transmission.

Photo of 6-speed automatic transmission
[Photo of 6-speed automatic transmission]

Compared to the 5-speed, the 6-speed automatic transmission applied to the new Sorento in Korea, for example, has 62 fewer parts, is 41mm shorter in length and 12kg lighter in weight, making it the most compact 6-speed transmission currently available. It produces a 10% improvement in fuel economy (14.1km/ℓ), 14% faster zero to 100km/h acceleration time (10.0 sec.) and 24% quicker 60km/h to 100km/h passing performance (5.0 sec.) (based on the Sorento diesel R-2.2 2WD).

The Theta 6-speed transmission for gasoline engines delivers an impressive 10.9 sec. acceleration time, 5.9 sec. passing performance and 10.7km/ℓ fuel economy.

What’s the difference between the previous 5-speed automatic and 6-speed automatic transaxle?

The new transmission provides better ride and acceleration during high-speed driving. The extra gear  provides better balanced performance during driving, thereby reducing the impact of shifting gears to deliver a more comfortable ride and quicker acceleration.

Fuel economy has been greatly enhanced. The extra gear means the engine doesn’t have to work as hard at high speeds, and thereby reducing fuel consumption.

For these reasons, the 6-speed transmission was previously only applied to premium lines like the Mohave (Borrego).

What are som of the key new technologies applied to the 6-speed automatic transmission?

The unique layout with three planetary gearsets and an ultra flat torque converter shorten the unit’s overall length by 12mm. Four pinion differentials improve durability while the hydraulic deviation adjustment valve body enhances shift quality. The low-viscosity automatic transmission fluid (ATF) and torque converter slip lock-up raise fuel efficiency.

[Ultra flat torque converter]

[4-pinion differential gears]

[Hydraulic deviation adjustment valve body]

In particular, the application of ATF and elimination of ATF level gauge (dipstick) reduces the need for maintenance and leads to further savings for customers.

What is the future application plan of the 6-speed automatic transmission?

The front-wheel drive 6-speed automatic transmission that was developed with 100% proprietary technology will be also applied to other Kia models, including the Opirus (Amanti) and Grand Carnival (Sedona).

  • ken wilks

    hi instead of working on so called new trans units why don`t you use a TORTRAK unit and be done with. this wiil give you many improvement including very good fuel comsumption

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  • Congrats on the 6-speed tranny development! I hope to see it applied to many new Kias.

    What I was wonderingabout transmission development is how far in the development are you with the dual clutch trannies and when can we expect to see it in Kia cars?

    For an example, a VW has a 7 speed dual clutch tranny applied in the new Golf, Passat and upcoming Polo sub-compact.

  • Peter

    So when can I put this in my V6 Rondo? Great work. If you get that into production, seems like you’ll beat Honda to it also.

  • admin

    To Himi

    We are already working on development of the Dual-Clutch Auto Transmission. But timeframe for application to Kia’s lineup has not yet been finalized.

  • Victor Foo

    Hello! I am just wondering about several thing. First of all, it is good that Kia has independently developed the six-speed transmission technology. What I would like to know is does the transmission technology actually belong to Hyundai or Kia develops the transmission technology solely on its own? Also, does Kia develop its own engine technology or use Hyundai’s engines? So, exactly what are all the engine and transmission technology does Kia develop independently and solely on its own?

  • Great to hear that Admin, you are really catching up with the “big boys”!

  • James

    Congrats on the autobox, but will we see a six-speed manual transmission too? That would really be a bold statement in a Kia “sportscar” and in other cars too.

  • admin

    Hi James,

    You will meet Forte Koup with six-speed manual transmission!
    I will definitely buy one with it! :)

  • Andrew Day

    do you know if there are going to be any changes for the forte for the 2011 model year?

  • Andrew Day

    for the sedan (see post above)

  • Colin


    There might be some changes to 2011 Forte.
    However, it is too early to talk about changes of 2011 Forte.

  • dindo aquino

    thanks for the info..crystal

  • And

    Is this transmission identical to Hyundai’s newly developed (They claim it to be their very own as well) 6 speed auto tranny?
    I’m aware that Kia and Hyundai are both owned by Hyundai Motor Company, but I’m just confused by the title of the article.
    Is this a Hyundai transmission or is it Kia’s? Or is it both…

  • Yehuda

    What kind of ATF the six speed needs?

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  • Kellie Sewell

    This is related to new Grand Carnival. Will the new Grand Carnival for release in Australia in June 2010 have the 2nd and 3rd row middle seats with a lap/sash belt to make the car safer.

  • Im grateful for the article. Will read on…

  • J Simmonds

    Having just driven the new Kia Sportage and finding it an absolute pleasure to drive and real world fuel savings as well. The engine is perfectly matched to the transmission for smooth operation.
    The only question in my mind is what has been done to eliminate the friction elements in the transmission. The clutch plates would have to be very durable to be able to actually withstand a maintenance free life. Conventional transmissions require a part fluid change every 40,000km to ensure longevity. I guess only time will tell how durable it really is.

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  • Waldus

    Interesting.  I’ll like to know if Kia is going to provide all the spare parts for this type of transmission or if they are going to provide the transmission as a sealed unit.  

  • Phil S

    In combination with your 2.2TD engine the 6-speed certainly makes the Grand Carnival drive more like a medium-performance car than, say, the Hyundai I-Max, which is very much a “Panel Van – meets MPV” arrangement.

    Wonder just how many V6 petrol engined Carnival owners will be planning to make the diesel upgrade? The 2.9 was very OK, but this new combination really blows the socks off the competition in terms of warranty, cost of operation, and fixed ownership costs.

  • Cabaneen_ca

    Want to know if a 6 speeds trany from a wrecked recent Sonata could be bolt to my 2.4 , L4 first gen theta Rondo motor . Bolt patern are the same ?  The 4 speed auto trany  realy suck in the Rondo ( Carens ’07-’12 ) Probably the donor Sonata would give their trany computer too ?

  • Fachrul Ruspandi Harahap

    I have a question my cars is koa carnival 2.5lt gasoline engine. My problem is the car can’t move retread where is the problem. Thanks for your unswer