Automobiles Review

Tag: Hydra-Matic 8L90

  • 2015 Yukon Denali Gets New Transmission

    2015-GMC-Yukon-Denali_thumb2015-GMC-Yukon-Denali_651

    The new 2015 GMC Yukon Denali has gotten a new transmission that brings numerous benefits to the vehicle including but not limited to higher horsepower, better torque and improved highway fuel economy. The new transmission is fully automatic and features 8 gears.

    Featured in the Yukon Denali and Yukon XL Denali the new Hydra-Matic 8L90 eight-speed automatic transmission is connected to the vehicles’ 6.2-liter EcoTec V8 engines and retires the older and less fuel efficient 6-speed automatic gearbox used until now in the Denali. Thanks to the new more advanced transmission the EPA highway mileage estimate for the two-wheel drive Yukon Denali and Yukon XL Denali increases to 22 mpg (10.7 l/100 km) while the EPA city mileage estimate for the four-wheel drive Yukon Denali rises to 15 mpg (15.7 l/100 km). The combination between the new 8-speed automatic transmission and the 6.2-liter V8 engine delivers a segment-leading 420 horsepower (309 kW) and 460 lb-ft (624 Nm) of torque along with highway fuel economy that can rival many other 6-cylinder and 8-cylinder engines in competitive makes.

    The new 8L90 transmission increases comfort by offering smaller steps between gears that allow the engine to efficiently leverage its peak power bands. The wider gearing spread also allows the use of a lower 3.23:1 rear axle ratio, which reduces engine speeds and fuel consumption, especially during highway cruising. Moreover the shift controls and solenoids of the 8L90 are more responsive and provide quicker shift times. A new torque converter also delivers smoother performance at low speeds, especially when carrying heavy loads or pulling trailers. Tow ratings – up to 8,400 pounds (3,814 kg) for the Yukon Denali and 8,100 pounds (3,677 kg) for the Yukon XL Denali – are unaffected by the addition of the eight-speed transmission.

    The new gearbox is not the only new thing that the two models provide. The 2015 GMC Yukon Denali and Yukon XL Denali feature other convenience and connectivity improvements such as:

    • A new hands-free power liftgate, which can be opened and closed by simply passing a foot beneath the rear bumper
    • A wireless charging surface for WPC (Qi) or PMA (Powermat) compatible mobile devices integrated into the design of the center console lid. A list of compatible devices is located at gmtotalconnect.com
    • OnStar with 4G LTE, which provides in-car data connectivity and a Wi-Fi hotspot capable of connecting up to seven devices at one time
    • An enhanced GMC Intellilink system, which provides incoming ‘Text Message Alerts’ when paired to a compatible Bluetooth phone

    Owners of 2015 Yukon and Yukon XL models can receive a tutorial on these new features through a new Yukon-specific application for tablet devices, which supplements the owner’s manual. The new Yukon app will be available for both Apple iOS and Android devices.

    The updated 2015 Yukon Denali and Yukon XL Denali models are priced from USD 64,965 and USD 67,665 respectively, and are now available at dealers.

    Source: GMC

  • Chevrolet talks about new Hydra-Matic 8L90 eight-speed transmission

    Hydra-Matic-8L90_thumbHydra-Matic-8L90_651The new 2015 Chevrolet Silverado has many features to boast with but Chevrolet is very proud to present the GM-developed Hydra-Matic 8L90 eight-speed transmission that is implemented in the vehicle. Indeed, this is a technological masterpiece and deserves some attention because apart from the engine, the transmission is the most important car feature that defines a vehicle.

    The new Hydra-Matic 8L90 eight-speed transmission is connected to a powerful 6.2-liter EcoTec V8 engine that is housed in the new 2015 Chevrolet Silverado and provides 11 per cent more torque than GM’s 6L80 six-speed automatic transmission. This along with the 6.2-liter EcoTec V8 engine that gives off 420 horsepower (309 kW) and 460 lb-ft (624 Nm) of torque is a combination that will satisfy everyone’s thirst for power.

    “The new 8L90 eight-speed is designed tougher to handle the greater power of the Silverado’s powertrains, with great improvements in spin loss to complement that capability with greater efficiency,” said Kavoos Kaveh, global chief engineer for eight-speed automatic transmissions. “It is a marvel of packaging efficiency and driving efficiency that has garnered more than two dozen patents for General Motors.”

    The Hydra-Matic 8L90 eight-speed transmission features four simple gearsets for optimal efficiency, five clutches (two brake clutches and three rotating ones) and innovative packaging that allows it to fit in the same space as the previous six-speed automatic with a lower weight. A wider 7.0 overall gear ratio spread provides a numerically higher 4.56 first gear ratio, helping drivers start off more confidently with a heavy load or when trailering. Smaller steps between gears, compared to the 6L80 (see chart below), keep the engine within the sweet spot of the rpm band, making the most of its horsepower and torque to optimize performance and efficiency. They also enable numerically lower rear axle ratios, which reduce engine rpm on the highway for reduced fuel consumption. The gearbox also features a number of friction-reducing technologies, including an all-new synthetic fluid and lower spin losses via a powerflow that uses only two open clutches. A new torque converter design with turbine damper enhances refinement, particularly during low-speed gear changes, for smoother performance when the truck is loaded or pulling a trailer.

    Similar to GM’s six-speed automatic design, the eight-speed’s architecture locates the grounding clutches rearward of the middle of the structure, outside the gearsets. However, the grounding clutches are splined to the case, eliminating the center support, which reduces weight. This architecture also features a turbine shaft node that reaches to the outside of the barrel, enabling easy execution of a high-resolution magnetic speed sensor. The turbine shaft itself is very short, keeping oil channel drill lengths to a minimum. The rotating clutches are located near the front of the transmission, with short oil feed channels, supporting very fast shifts.

    There are many other features that this revolutionary gearbox comes with such as an industry-first off-axis, chain-driven binary vane-type pump that allows for two pumps in the packaging size of a single, a 60-percent reduction in pump torque at points that represent large portions of the operating duty cycle, compared to the 6L80 six-speed, a new torque converter clutch friction lining and a new control strategy and more.

    The new 8L90 is built at GM’s Toledo, Ohio, transmission facility.

    Source: Chevrolet

  • Eight-speed transmission to debut in select Chevrolet and GMC vehicles

    The US car brands of Chevrolet and GMC, fully owned by General Motors, have confirmed that certain Chevy and GMC models will receive a new eight-speed automatic transmission starting in 2015. The new models that will boast this gearbox will be the 2015 Chevrolet Silverado and the GMC Sierra and GMC Yukon Denali/Yukon XL Denali models that come with 6.2-liter EcoTec3 V8 engines.

    The new transmission is called Hydra-Matic 8L90 and has been developed by GM. It comes with about the same size and weight as the Hydra-Matic 6L90 six-speed automatic gearbox. Its 7.0 overall gear ratio spread is wider than GM’s six-speed automatic transmissions, providing a numerically higher first gear ratio to help drivers start off more confidently with a heavy load or when trailering. The 8L90 also enables numerically lower rear axle ratios, which reduce engine rpm on the highway.

    The 6.2-liter EcoTec V8 engine is also impressive – it offers 309 kW (420 HP) of power and 460 lb.-ft. (624 Nm) of torque as well as a maximum available trailer rating of 12 000 pounds (5448 kilograms), based on the SAE J2807 Recommended Practices. Just like many other EcoTec3 engines, it can also work with four cylinders only under lighter loads to improve fuel efficiency.

    More information on the 6.2-liter EcoTec V8 engine will become available when the unit enters production, which will be in Q4 2014.

    Source: GM