General Motors is launching a new 9-speed automatic transmission for use in front-wheel-drive passenger vehicles, and thanks to a thorough technical backgrounder event hosted by the automaker, we’ve got all the details for you right here.
What Is It?
An all-new, transverse Hydra-Matic planetary automatic transmission dubbed “9T50,” based on GM’s existing 6-speed transverse automatic transmission. The unit’s design and engineering are being shared with Ford Motor Company, in exchange for the right to use a new, Ford-developed 10-speed longitudinal automatic in products like the Chevrolet Camaro ZL1. It’s a sort of “two transmissions for the cost of one” deal for GM and Ford.
The Hydra-Matic 9T50 will be produced at GM’s San Luis Potosi plant in Mexico.
What Are The Applications?
General Motors was rather clear that this new 9-speed automatic is a “premium” unit, but that’s not to say that it will be reserved for the likes of Buick and Cadillac; it debuts in the 2017 Chevrolet Malibu 2.0T, and will later be made available in the 2017 Cruze (with 1.6L turbo diesel) and 2018 Equinox (with 2.0T), finding its way to an additional seven models by the end of 2017. Not only can it be used in FWD gas and diesel applications, but it’s four-wheel-drive-ready, as well.
This new, transverse 9-speed is anything but a “niche” product.
How Does It Compare To GM’s 6-Speed Transverse Automatic?
Quite favorably. The unit is just 10 kg heavier – about 22 pounds – despite containing an additional planetary gearset and all the kit that goes with it (solenoids, valves, etc). According to General Motors, the packaging is roughly the same, meaning that it can be deployed pretty much wherever the 6-speed is currently in use.
The new 9-speed’s additional ratios mean it’s better able to match the engine with an appropriate forward gear that optimizes its operation, whether the driver wants to keep within the power band or keep RPM low for efficiency. It nonetheless has a wider ratio spread than GM’s 6-speed transverse automatic – 7.6:1 versus 6.0:1 – with two overdrive ratios as opposed to just one.
And then, there are new technologies present, including an “Active Oil Management” system that takes up excess fluid volume in the transmission case as the oil heats and expands, and an industry-first “Selectable One-Way Clutch” in a transmission application. The clutch, which controls the engagement of first- and reverse-gear, enables smooth coasting in first and improves the shift feel from first- to second-gear, all while reducing mass and packaging space compared to the plate clutch pack and sprag clutch it replaces.
General Motors’ new 9-speed transverse automatic represents some of the best transmission engineering in the world to-date. The 6-speed Hydra-Matic from which it sprang is already a peach; GM says that independent shift-quality scores are among the best in the world, and it earns top marks for reliability and durability, too.
Turning that winning 6-speed into a brand-new 9-speed automatic required more than 60 new patents and countless man hours. The result is a transmission that weighs virtually the same, occupies about the same amount of space, and promises greater performance and efficiency without any unsavory NVH. We’d call that a win.