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Deep Dive: GM’s New 9-Speed Automatic Transmission

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.

Conclusion

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.

Aaron Brzozowski is a writer and motoring enthusiast from Detroit with an affinity for '80s German steel. He is not active on the Twitter these days, but you may send him a courier pigeon.

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Comments

  1. GM is the world’s leader in automatic transmission since the 1950’s. Even Rolls-Royce, the best Englisth luxury brand, used GM transmissions in their models, and now has a license to reproduce them (look it up if you don’t believe me). This 9ET50 may be the unit that was produced with a Ford cross-design agreement, but GM has a much better unit for all FWD: the Volt’s 5ET50 Electric Drive Unit . This new EDU can vary with all speeds from 0 to 99 MPH smothly because the main propulsion is electric (no shifts at all). And it is also used in the Malibu Hybrid, so GM Authority should compare both Malibu versions and see which is really “smoother” and quieter.

    My bet goes to the 5ET50!

    Reply
  2. I wonder if it will find its way to the Envision as the Equinox already have the 9 speed

    Reply
  3. I question GM’s (and Ford’s) enthusiasm over their claimed 7.6:1 overall range, where the ZF 9-speed has a 9.8:1 range. Therefore, the ZF unit has lower (numerically higher) first gear and a taller (numerically lower) final gear.

    Tell me again why this new tranny is so cutting edge. . .?

    Reply
    1. right the colorado has nothing but problems with that tranny
      pos

      Reply
    2. Why would the trans necessarily need a wide range to increase fuel efficiency the most?What are the weights and dimensions of the units?

      Reply
    3. The ZF 9 speed is one of the worst most problematic transmissions in production right now. It’s causing a lot of grief for every manufacture using it.

      Reply
      1. Not really. We have most of the bugs except for debris problems worked out of the 9 speed. 14 and 15 model year trans had old valve bodies and old software. 16 and up shift a lot smoother and are hardly having any warranty problems.

        Reply
  4. I have one of these in my 2017 Malibu 2.0T. I have 2900 miles on the car and like how it works. I have accelerated hard, but not full-throttle acceleration. It seem to shift quickly under fast acceleration as seen on the tachometer but I have no idea what gear I am in at any one time. As an end-user, I wouldn’t know it had 9 gears given observations from operation of the vehicle.

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    1. the colorado i mensioned, and it is mostly due to calibration although lot of then have faulty torque converter that i know of.

      Reply
  5. New 9 speed automatic transmission with new e assist/mildhybrid system, for Chevrolet crossovers, yes?

    Reply

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