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2006 Cadillac STS-V: Transmission
By Jacob Isaac-Lowry
Jan 18, 2005, 17:18

2006 CADILLAC STS-V: TRANSMISSION
GM Powertrain Launches New Hydra-matic Six-speed Transmission


  • New six-speed rear-wheel-drive (RWD) transmissions designed from clean sheet as Hydra-Matic's first-ever modular transmission family
  • Four-variant lineup applicable to RWD or AWD/4WD cars and trucks; torque capacity from 258 lb.-ft. to 520 lb.-ft. (350 Nm to 705 Nm) with flexibility for future growth
  • First production variant: 6L80 for Cadillac STS-V
  • Designed for global use, manufactured in North America and Europe
  • Modular architecture and agile manufacturing enable highly flexible production environment


    DETROIT - GM Powertrain unveils an all-new family of Hydra-Matic rear-wheel-drive (RWD) six-speed automatic transmissions designed to deliver new levels of performance and efficiency for GM products throughout the world. The new six-speed automatic transmission family is comprised of four distinct variants developed and built to advance Hydra-Matic's 65-year tradition of building world-class automatic transmissions. Introduction of this new transmission family marks the beginning of a GM initiative to produce nearly 1 million six-speed automatic transmissions annually by 2008.

    "This is the first GM Powertrain transmission designed as a family," said Jeffrey K. Baran, chief engineer, six-speed RWD transmission family. "That means we can incorporate the best technologies for a wide 'bandwidth' of current and future vehicle applications. The new, modular architecture was critical in ensuring the exceptional performance and manufacturing targets we set - it provides outstanding development and manufacturing flexibility."

    Engineering of Hydra-Matic's new six-speed RWD transmission was a genuinely global effort. GM Powertrain leveraged the expertise of transmission specialists from its U.S., GM Europe and Allison engineering units. "We used knowledge and experience from the entire GM Powertrain network to engineer this transmission," said Baran. The new six-speed automatic incorporates the most advanced technology Hydra-Matic has ever packed into an automatic transmission. The modular design, meanwhile, facilitates application across a broad range of vehicle architectures - from RWD cars to four- and all-wheel-drive pickups, SUVs and crossover vehicles. Modular construction also enables an easy plug-and-play approach to delivering features and hardware for specific vehicles.

    "This transmission architecture was designed to satisfy a large matrix of attributes for current and future vehicle programs," he added. "It's the first GM transmission ever designed in this way."

    Modular Strategy Enables Flexible Technology and Manufacturing
    Engineering the all-new Hydra-Matic six-speed transmission with a modular architecture enabled engineers and designers to design a transmission that is easily adapted to a wide range of vehicles. Equally important, the new six-speed automatic's modular design means any of the four primary variants can be manufactured in the same assembly plant.

    Cutaway View of the All New Six-speed GM Automatic Used in the STS-V
    "We spent a lot of time engineering at the architecture level," said Kavoos Kaveh, assistant chief engineer. That thinking led to a "systems engineering" approach that results in just three main pieces to comprise the entire outer "case" of any variant of the new six-speed automatic. Thanks to this engineered-in modularity, the difference in length between the largest and smallest of Hydra-Matic's newest transmissions is less than 50 mm. Additionally, the "locators" used throughout the manufacture and assembly of the bellhousings and main cases are common to all variants, greatly simplifying the task of building different variants on the same production line. This manufacturing flexibility generates marked cost savings, but there's another important benefit: The assembly plant can quickly and efficiently move from producing one variant to another. This gives the transmission assembly plant unprecedented flexibility to respond to rapidly changing market conditions - an advantage unavailable to plants building non-modular automatic transmissions. According to Dennis Provenzano, program manager, the new transmission design is so flexible that different variants theoretically could run sequentially down the same assembly line. He adds that the new six-speed automatic's manufacturing plan dovetails completely with GM's Global Manufacturing System strategy to implement a common manufacturing process and procedure at every worldwide GM assembly plant. It all means the new six-speed RWD automatic will maintain Hydra-Matic's reputation for world-class refinement and durability while continuing GM Powertrain's ongoing initiative to produce durable and reliable engines and transmissions.

    Built-in Flexibility Enables Advanced Technology
    The modular architecture of the all-new Hydra-Matic six-speed automatic generates benefits beyond the manufacturing site. The design enabled engineers to develop one of the most sophisticated automatic transmissions GM Powertrain has ever built. Several features make the new six-speed automatic an important design milestone in Hydra-Matic's 65-year history of automatic transmissions:

    Truly modular design: as many as 47 percent of all components are common to all variants
    Just four distinct output and input gearsets are needed for all variants
    Innovative clutch-to-clutch operation reduces the number of torque-handling components while simultaneously improving shift quality and overall refinement
    Wide 6.04:1 overall ratio enhances performance, fuel economy
    The sophisticated transmission control module was engineered to incorporate all electro-hydraulic components, as well as the transmission controller. The 32-bit transmission controller is common to all variants and is located entirely within the transmission housing
    GM Powertrain's advanced, model-based controls strategy is developed and validated completely in-house - not outsourced to suppliers as many competitors do - and leverages extensive experience GM engineers have gleaned from development of all Hydra-Matic transmission-control software
    Ability to easily incorporate advanced performance features such as Driver Shift Control (sequential manual shifting), Advanced Performance Algorithm Shifting (PAS) and grade braking
    Durability testing under rigorous performance car and truck duty cycles


    Because the new six-speed automatic's design incorporates a high degree of commonality, it allows greater flexibility in specifying the torque-carrying components specific to each individual transmission in the family. The result is that the transmission will be used in as many as 25 vehicle models by 2007. Meanwhile, the generous 6.04:1 overall ratio enables a "steep" first-gear ratio that helps deliver strong launch acceleration, yet also provides for "tall" overdrive ratios that decrease engine rpm to enhance fuel economy and reduce noise when cruising. GM engineers estimate the wide ratio spread will help cut 0-60 mph times by as much as 7 percent when compared to current four- and five-speed automatics. The new Hydra-Matic six-speed automatic transmission is GM Powertrain's first automatic-transmission architecture to employ an internal controller; the unit is located entirely within the transmission and operates while bathed in transmission fluid. Locating the controller internally facilitates the modular design and assembly strategy while shielding the unit from the outside environment. Meanwhile, GM's proprietary model-based controls strategy reaches a greater level of sophistication in the new six-speed RWD transmission family. The 32-bit system incorporates three levels of "learning" that actually allow the components to adapt to one another.

    Although it is not uncommon to have a transmission-control module that adapts to the specific transmission with which it is mated, and to also have programming that optimizes transmission performance characteristics according to a variety of vehicle inputs, the new Hydra-Matic six-speed automatic adds another level of adaptability. Certain components within the seven major subsystems that make up the transmission also "learn" from one another - via the controller software - in a unique form of self-adaptation that maximizes the interface of all the networked components. This procedure takes place as the transmission "tests" itself and the interaction of its internal components before it is shipped from the assembly plant.

    Hydra-Matic Six-speed Automatic Fast Facts:
    First GM Powertrain automatic transmission designed from the onset as a modular architecture
    Four distinct variants launched in 25 vehicle models by 2007
    Applicable to RWD, 4WD and AWD powertrain layouts
    Torque capacity from 258 lb.-ft. to 520 lb.-ft.
    Shift speeds up to 7000 rpm
    32-bit intelligent controller
    Designed and engineered by GM Powertrain experts in North America and Europe
    Built in GM Powertrain assembly plants in Ypsilanti, Mich., and Strasbourg, France
    First vehicle application: 2006 Cadillac STS-V





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