Doing It Again — This Time With 10

July 1, 2016

Bill Visnic

Almost exactly a decade after Ford and General Motors initiated production of 6-speed planetary-gear automatics derived from the two companies’ first-ever transmission-development collaboration, the Detroit behemoths are at it again. In the coming months, each company will launch a specialty model showcasing an all-new 10-speed automatic that is ultimately earmarked for some of the respective companies’ highest-volume products: full-size pickup trucks.

The new 10-speed automatic is the result of a four-year joint development program first confirmed in 2013. It is intended primarily for rear-drive or four-wheel-drive vehicles with longitudinally-mounted engines (see sidebar). The two companies’ engineering teams concurrently developed a 9-speed automatic transaxle for front- or all-wheel-drive models with transversely-mounted engines; applications for that transmission have yet to be announced.

It is understood that Ford Powertrain led the fundamental engineering and development of the 10-speed while GM Global Propulsion Systems led that of the 9-speed unit.

Both transmissions were developed to wring yet more efficiency from the step-gear torque-converter automatics American drivers so avidly embrace, providing improved acceleration and enabling lower numeric axle ratios for improved highway and city fuel economy. They also address several of the performance and driveability foibles of current multi-speed automatics, Kevin Norris, Ford’s manager of 10R transmission systems, told Automotive Engineering during an interview at the 2016 CTI Transmission Symposium where Ford presented details of the new 10-speed automatic.

Incidentally, Ford has internally coded the transmission the 10R80, while a GM source said the company’s Global Propulsion Systems unit has yet to apply an internal designation. Their version is currently referred to only as a Hydra-Matic but it is expected to be named 10L80 or 90, following GM’s longstanding nomenclature.

For GM, the 10-speed automatic launches in late 2016 in the ultra-performance 2017 Chevrolet Camaro ZL1. Ford’s first application will be similarly severe-duty: the 2017 F-150 Raptor powered by a new 3.5-L Ecoboost V6. Although neither company has yet confirmed the transmission’s application for mainstream full-size pickups, it’s widely known that’s the end game. GM has said the 10-speed will be used by 18 different models by the end of 2018.

Automotive Engineering has learned that Ford is investigating a 10-speed capable of handling 1000 lb·ft (1356 N·m) inputs, for use with Super Duty diesel trucks. GM is separately developing its own 10-speed for medium-duty applications, coded AB1V and expected to debut in late 2019, according to transmission-supplier sources.

Inside the box

For engineers starting with this clean-sheet design, expanding the physical package wasn’t much of an option. The new 10-speed automatic needed to offer a hassle-free fit with existing-vehicle interfaces, so thousands of hours of CAE design generated key dimensions that effectively are the same as the 6- and 8-speed automatics currently used by both companies.

This was no mean effort and dictated a variety of clever space-saving solutions: an integrated turbine clutch saved 10 mm (.39 in) of axial space and chopped a kilogram (2.2-lb) of mass. A special triple-clutch assembly in the middle of it all is a primary enabler for packaging 10-speed content in the same [longitudinal] space as 6- and 8-speed automatics, according to GM engineers.

The standard-equipment electronic pump that coordinates with the engine’s stop-start functionality is integrated directly into the transmission, as are all the direct-acting hydraulic controls.

The new 10-speed (the top three ratios are overdrive) is housed in a one-piece aluminum case with an integral bell housing. The primary mechanicals consist of four planetary gearsets and six clutches — four clutches are rotating and two are brake clutches. Despite having two more forward ratios than the 8-speed automatic GM currently uses, the company said the new transmission adds just one more clutch. This helps minimize package size while reducing the spin losses the two companies’ engineers identified as a primary target to improve efficiency.

The healthy overall ratio span of 7.4 also came as no accident, said Ford’s Norris, as powerful kinematic search software helped engineers determine optimum ring and sun-gear ratios, gear speeds, spans and ratio progressions and even evaluate the hardware matrix in terms of cost and fuel-efficiency potential. And key for the customer, he said, was the focus on kinematics control which “really helped us to improve dynamics and responsiveness.”

The 7.4 ratio spread is about the maximum current research says is usable on the road, Norris added. So, too, for the 10 forward ratios. “Beyond about 7.5 (overall ratio), we see little gain,” he said. And while analysis indicated opportunity for gains at more than eight ratios, beyond 10 ratios “we see the benefits start to decline.” Design software determined the transmission’s overall component count also was optimized at ten speeds.

Transmission junkies will be interested in the “return” of a roller one-way clutch, a bit of a throwback in transmission design. The one-way clutch is an important “schedule enabler” for shift programming to mitigate driveline lash and Norris claims it also eradicates the lazy-feeling low-speed throttle tip-in that plagues many multispeed automatics.

According to supplier sources related to the 10-speed program, GM and Ford are licensing certain elements of the 10-speed clutching system from ZF TRW, due to the German driveline supplier’s broad clutch-technology patents.

Of spin losses and shift times

Although the 3-4% improvement in fuel economy compared to 6-speed automatics (an up to 2% gain versus GM’s 8-speed) was the primary raison d’etre for Ford and GM’s 10-speed automatic, the clean-sheet opportunity was used as a springboard to address performance, refinement and driveability concerns some find with existing multi-speed automatics. GM and Ford engineers concede, however, that most incumbent multi-speed automatics generally operate with laudable refinement.

Norris adds that the quality of shifts is on a similar high level and that this transmission in all its applications, unlike some other multispeed automatics, will use all its gears.

“Customers will routinely see tenth gear at highway speeds,” he promised.

Moreover, the transmission’s small steps and intense shift-schedule optimization mean the crucial 9-to-10 step is virtually unnoticeable. Said Norris: “We’ve reached the point where that’s really an imperceptible shift.”

Then there are the outright performance advantages of 10 tightly stacked ratios. Data developed by GM indicates the 10-speed automatic delivers upshift times that are markedly quicker than Porsche’s bench-mark dual-clutch PDK automated-manual transmission.

“With shift times on par with the world’s best dual-clutch transmissions and the refinement that comes only from a true automatic, the 10-speed delivers incomparable performance on and off the track,” said Dan Nicholson, Vice President, GM Global Propulsion Systems, in a statement.

Norris said those towing with a 10-speed equipped vehicle also will be similarly impressed: “Overall, the trailer-tow experience is more comfortable and competent.” The closely spaced ratios enable lower-rpm shift speeds at wide-open throttle (WOT) and make more of the engine’s power available in the higher gear ratios — enhanced performance that should be apparent in nearly all driving situations.

Although Ford has not yet released individual gear ratios for the 10-speed automatic as installed in the 2017 F-150 Raptor, GM Global Propulsion Systems did detail gear ratios compared with its 8-speed automatic. The numbers indicate a first gear ratio of 4.70:1 for the new 10-speed compared with 4.56:1 for the 8-speed, while direct drive occurs in sixth gear for the 8-speed automatic and seventh gear for the new 10-speed. The 8, 9, and 10 overdrive gears have respective ratios at 0.85, 0.69 and 0.64.

Additional innovations

The two companies’ transmission designers baked in a few other advanced features, most aimed at improving efficiency. A variable-displacement vane pump is offset-mounted, cutting torque losses and simultaneously improving high-speed NVH. New ultra-low-viscosity transmission fluid (surprisingly, not fully synthetic) delivers the expected benefit of any lower-viscosity fluid, but also cuts the tendency for “squawk.”

An internal thermal bypass hastens warmup, bringing the 10-speed more quickly to normal operating temperature, which enhances fuel economy. And in addition to the integrated e-pump for ideal collaboration with engine stop-start functionality, the new automatic also is designed with integrated capability for shift-by-wire control.

In a few months, journalists will have the first on-the-road impressions in the 2017 Camaro ZL1 and F-150 Raptor. But you don’t have to wait for the verdict: Ford’s Norris, with as little bias as is possible from the person leading his company’s development team, is certain the all-new 10-speed automatic won’t disappoint.

“It’s really exhilarating,” he promises.

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