Next-gen GM six-speed automatic to boost mileage another 5 percent
It's only been a year since General Motors launched its 6T40 six-speed automatic transmission for mid-size and compact cars. When it was introduced, this new transmission brought with it a five percent bump in fuel efficiency. The engineers at GM Powertrain are now developing a second generation variant of the 6T40 for introduction in 2011 that will bump fuel efficiency by yet another five percent. The new version will have updated electronic control strategies based on the work done for the new 2011 Chevy Equinox with the four-cylinder engine. The Equinox manages a 32 mpg highway rating. These new controls developed for the Equinox will contribute three percent of the improvement for 2012 models like the Cruze compact.
Another two percent improvement will come from refinements to the guts of the transmission. Changes to the hydraulic valve body, friction plates and variable flow solenoid will cut internal pumping losses and friction.
GM is also working on its own in-house developed dual clutch transmissions. GMPT is developing a dry clutch system that should yield another incremental improvement in efficiency, but no announcement was forthcoming about timing.
[Source: General Motors]
Reader Comments (Page 1 of 3)
ToyotaGuy 5:23PM (8/14/2009)
I see GM is still trying HARD to beat toyota, but they always end up having an epic fail.
"The Equinox manages a 32 mpg highway rating" WOW.
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dal20402 5:15PM (8/14/2009)
So you think your RAV4's 27 highway rating is better? I see no "epic fail" in getting a comfortable, affordable CUV to have the mileage of a compact car.
timwang2006 5:23PM (8/14/2009)
@ToyotaGuy
Your name makes you lose all credibility when it comes to an unbiased argument. As good as Toyota's are, the guts of the RAV4 drive train has been around 2001 and isn't exactly what I would call class leading. 32MPG isn't any kind of fail at all.
XGM 5:26PM (8/14/2009)
How nice, a fanboy who joins us today. If I wanted a appliance id drive a Toyota, but seeing as most of us are enthusiasts here and prefer something engaging GM has a better offering.
Generic.User 5:28PM (8/14/2009)
Voted down for the unintelligent comment.
RK 5:31PM (8/14/2009)
I also root for the Japanese baseball team when they come over here. NOT.
Dan 6:20PM (8/14/2009)
"the guts of the RAV4 drive train has been around 2001 and isn't exactly what I would call class leading."
The RAV4 I4 was new for MY2009 and is thoroughly modern in all regards. The transmission is a dinosaur.
Bill 8:08PM (8/14/2009)
I'm so sick of the phrases "fail" and "epic fail". Will you 21-year olds please put down your iPhone and text-chat phones, read a real book, and add a few more words to your English vocabulary.
evident 9:15PM (8/14/2009)
i wouldn't call the equinox engaging either, fanboy.
Evan 8:23AM (8/15/2009)
Equinox or RAV4, they are both fundamentally flawed automobiles. Their height destroys their aerodynamics and handling. Why can't Americans buy normal hatchbacks or estates that aren't disguised as SUVs?
the friendly grizzly 4:52PM (8/15/2009)
Yes, Dal. the 27 in his RAV4 is better. Why? well, because... uhh... it's a Toyota, that's why. That's all you need to know.
WestCoastPaul 5:18PM (8/14/2009)
It's so refreshing to see good news coming out of the GM Camp. I believe that many want more reasons to buy US and news of fuel efficiency, electric cars, Hot looking Camero's are just the beginning. Go GM!
May the US lead again..
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RK 5:29PM (8/14/2009)
Maybe Nissan should inquire about those twin clutch transmissions ;)
MikeW 6:32PM (8/14/2009)
If that dual range CVT design is scaled up to the high torque versions of the CVT, then Nissan can get a few more years from CVTs.
If the ratio spread increases from 5.4:1 to 6.6:1, that would be great.
Ike 7:12PM (8/14/2009)
Add "reliable mechanics, seals, and electronics" to the list of what people want. Historically, the domestics have failed miserably in these areas, which is why the Japanese have such a huge chunk of the market... Any thoughts, anyone?
Gary 7:56PM (8/14/2009)
I know somebody who ran into automatic transmission problems with both his Civics.
Tool 2:33AM (8/15/2009)
I seem to recall Bob Lutz telling us that it was going to cost an additional $5,000 per vehicle to make them more fuel efficient and environmental friendly.
Guess those scare tactics weren't true. (Edit: Kind of like the scare tactics of the Right on healthcare, but that is another rant).
What is good to see is that these MPG improvements will come in 5% increments like this. When you add all the improvements together you can see how easy it would be to make our vehicles more fuel efficient.
knightuc1992 8:51AM (8/15/2009)
How much you want to bet the capabilities of this transmission will be diminished after GM's beancounters finish cost-cutting the hell out of it?
Conundrum 10:00PM (8/15/2009)
@ Ike...
GM powertrains are some of the best in the business. I guess you would have preferred to own one of the 1.2 million honda five speed transmissions that were not designed properly for Accords and affiliated models causing a high failure rate. Maybe one of the 600,000 Honda transmissions that were later recalled in Oddyssey, Pilot and MDX vehicles. Perhaps one of those grinding Honda six speed manual trannies? Oh yeah what trim of 2009 Accord is avaliable with a six speed auto?... That's what I thought!
adam1drift 5:45PM (8/14/2009)
now if we can get ford to get some 6 speed gear boxes especially in the mustang!
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