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Could This Be The C7 Z06's New Transmission?

14K views 51 replies 25 participants last post by  Cphelps 
#1 · (Edited by Moderator)
General Motors Rear Wheel Drive Eight Speed Automatic Transmission
SAE International
by James Michael Hart, Tejinder Singh, William Goodrich
April 1, 2014

"General Motors Rear Wheel Drive Eight Speed Automatic Transmission General Motors shall introduce a new rear wheel drive eight speed automatic transmission, known as the 8L90, in the 2015 Chevrolet Corvette. The rated turbine torque capacity is 1000 Nm. This transmission replaces the venerable 6L80 six speed automatic transmission.

The objectives behind creation of this transmission are improved fuel economy, performance, and NVH. Packaging in the existing vehicle architecture and high mileage dependability are the givens. The architecture is required to offer low cost for a rear drive eight speed transmission while meeting the givens and objectives.

An eight speed powerflow, invented by General Motors, was selected. This powerflow yields a 7.0 overall ratio spread, enabling improved launch capability because of a deeper first gear ratio and better fuel economy due to lower top gear N/V capability, relative to the 6L80. The eight speed ratios are generated using four simple planetary gearsets, two brake clutches and three rotating clutches. The resultant on-axis transmission architecture utilizes a squashed torque converter, an off-axis pump and four close coupled gearsets."

Full article at link.
 
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#9 ·
From an earlier article at Wards Auto:

More recently, we’ve learned the program had indeed been in flux at GM, but given how far development had come and the fact the automatic likely will be sold to other auto makers, it made sense to continue. More intriguing, however, is the fact that the automatic will not appear in the large pickups, SUVs and beefy sports cars as originally, and perhaps wrongly, assumed.

The 8-speed, in fact, likely will appear first in GM models based off the current Sigma and Alpha platforms, according to a WardsAuto/AutomotiveCompass forecast. That means 4-cyl. and naturally aspirated V-6 engine models of the Cadillac CTS, ATS, XTS and the next Chevy Camaro. It also will appear in models meant for export that will not be sold in North America.
Hmm.
 
#20 ·
Well if this is all true I think we may see a very fast roll out. At the end of the SAE link it says:

Packaging is within that of the GM 6L80 design, allowing for ease of application integration. The overall result is a robust, compact, and cost effective transmission which offers significant fuel economy and performance benefit, over its six speed counterpart, and shall provide an attractive balance of overall metrics in the automatic transmission market.
 
#23 ·
I don't think this is targeted at the Z06, which in the past was only offered with a manual. I suspect all automatic Stingrays will be using this transmission thereby ending the existence of any six-speed Vette. It seems likely that this will also propagate to other RWD applications, especially those running versions of the Chevy small block, though that will take some time to disseminate (for instance, the 5th gen Camaro will probably not see the 8-speed in time, but the 6th gen will). It would make sense for a version to go into the SUVs and full size pick ups, but I suspect further engineering will be required to get it working with 4WD drivetrains. Lastly, the FWD/AWD transmissions are completely separate from this unit, plus they are supposed to have 9 or 10 speeds if I recall correctly, and are co developed with Ford (also not to be confused with the outsourced 8-speed Aisin unit in the new CTS).
 
#32 ·
It would make sense for a version to go into the SUVs and full size pick ups, but I suspect further engineering will be required to get it working with 4WD drivetrains.
I personally don't see why further engineering would be needed to work with 4WD. BOF style 4WD requires a transfer case. I like to think that the only difference between a RWD & a 4WD would be the transfer case. The RWD driveshaft bolting up to the transmission output shaft while the 4WD would have the transfer case input shaft connected to the output shaft of the trans. The 8-speed in the article is claimed to be right about the size of the common 6A that GM uses now.

"DETROIT – Ford Motor Co. and General Motors Co. have signed an agreement under which both companies will jointly develop an all-new generation of advanced technology 9- and 10-speed automatic transmissions for cars, crossovers, SUVs and trucks.

The new transmissions, to be built in both front- and rear-wheel drive variants, will improve vehicle performance and increase fuel economy.
" http://media.gm.com/media/us/en/gm/news.detail.html/content/Pages/news/us/en/2013/Apr/0415-transmission.html

I'm thinking the 8speed will be exclusively for performance (Vettes/CTSs/Omega/ATSs) and high end vehicles (Escalade/Denalis/LTZ/High-Country) looking at that torque capability.

I think the 9/10 speed will be for everything else.
I thought the 9-speeds were for the FWD vehicles while the 10-speeds were for trucks/SUVs. Pretty soon the F150 will come with the Mustang's 2.3L EB & a 10-speed auto transmission. :lmao:
 
#36 ·
The date of the article is APRIL 1 st 2014.

APRIL FOOLS DAY

Z06 will most probably be manual transmission only

Not that an 8 speed automatic would be bad..

I expect that version to be the quickest considering the advances in technology
 
#44 ·
Could an 8 speed auto be the Z06's trans? I would be literally shocked if we were to see a Z06 with an automatic; though I suppose it wouldn't be so crazy since it's looking like they may be going with forced induction as well this time around.
 
#47 ·
One could say the Z51 is even more suitable for the track because it's naturally aspirated, but it has an auto. 8 speeds like the ZF are pretty impressive, providing better NVH than DCTs while still providing crisp, accurate, and extremely fast shift times. If you want the fastest car, it’s going to be the auto.

Ultimately, Corvettes are road cars, just like Ferraris. There’s no reason not to offer both options. The Z06 and Viper are about the only supercars on the planet without autos. It’s the standard now and expected.
 
#46 ·
the C-7 corvette was to have a 8 speed auto but the GM one was not ready and GM did not want to use japanese build one in a corvette like they do in the caddy
 
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