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GM Launches More Fuel-Saving Six-Speed

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FOR RELEASE: 2006-05-18

GM Launches More Fuel-Saving Six-Speed Automatic Transmissions

PONTIAC , Mich. –GM’s plan to offer one million vehicles annually with six-speed automatics by 2008 accelerates in 2006 and 2007 with nearly 40 global vehicle applications of the fuel-saving transmissions. Models of the 2007 Cadillac STS and SRX, as well as the Saturn Aura, Outlook and Pontiac G6, highlight the vehicles offered with new six-speed automatics.

Other models already on sale include the GMC Yukon Denali family, the Cadillac XLR-V, STS-V and Escalade lineup, and the Chevrolet Corvette. GM’s full-size heavy duty pickups are also equipped with an Allison 1000 six-speed automatic when equipped with the Duramax 6.6L turbo-diesel engine.

New 2007 model year six-speed automatic transmission variants include the Hydra-Matic 6T70 and 6T75 for front and all-wheel drive vehicles, as well as the Hydra-Matic 6L50 for rear and all-wheel drive vehicles. The 6L50 benefits from the expertise developed with the larger 6L80 rear-wheel drive six-speed transmission (initially in the 2006 model year), and is the second variant in the Hydra-Matic rear-wheel drive six-speed transmission family.

Advantages of a six-speed automatic include improved fuel economy, performance and a shift feel that is seamless to the customer. The six-speed automatic enables a reduced engine rpm at highway cruising speeds. A lower engine speed reduces engine wear and noise, and improves fuel economy.

“It’s a best-of-both-worlds scenario with the six-speed automatic, delivering great performance and enabling improved fuel economy,” said Jim Lanzon, executive director of transmission engineering for GM Powertrain. “It is almost like having two transmissions in one – the high numerical first gear provides tremendous off-the-line acceleration, but the transmission is able to use the six gears to evenly distribute the torque and settle at an overdrive gear that helps deliver great fuel economy.”

Vehicle performance is enhanced with a six-speed, because smaller “steps” are used between gears, compared to a conventional four-speed automatic. This allows the transmission to quickly find the best gear for the vehicle speed and road conditions – there’s less back-and-forth hunting on grades, for example. GM’s new Hydra-Matic six-speeds also use technically advanced clutch-to-clutch operation, which reduces mass, complexity and enables compact packaging. A wide, 6.04:1 overall ratio on most of GM’s six-speeds, compared to 4.0 of typical four-speed automatics, delivers both great performance and improved fuel economy.

“The mechanical simplicity of the clutch-to-clutch shift operation in our new six-speed automatic transmission families, along with a conscious effort to reduce part complexity, is providing us greater flexibility and the ability to launch with a broad application across the GM portfolio,” said Lanzon. “By 2010, GM will introduce 10 new variants of six-speed automatic transmissions, producing three million six-speeds annually.”

GM’s six-speed transmissions also provide tremendous flexibility to customize features for each vehicle brand, such as tapshift range selection, auto grade braking and a tow/haul mode.

New 6T70 and 6T75 FWD transmissions

The new Hydra-Matic 6T70 and 6T75 six-speed automatics are advanced transmissions with clutch-to-clutch shift operation for front- and all-wheel drive vehicles. The transmissions are based on a common design, with the 6T75 rated for higher torque capacity. The 6T70 debuts on the Saturn Aura and on a Pontiac G6 model; the 6T75 will be offered on the Saturn Outlook

The 6T70/75’s clutch-to-clutch operation and 6.04:1 overall ratio help the transmission deliver both performance and fuel economy, enabling up to 7 percent improved performance and up to 4 percent improved fuel economy when compared with current front-wheel drive four-speed automatics. Both transmissions use a very high numerical 4.48:1 first gear, which helps deliver exceptional launch feel, and a 0.74:1 overdrive sixth gear, which reduces engine rpms at high speeds, thereby reducing engine noise and vibrations. Fifth gear is 1:1 direct drive.

With its wide ratio and strong capacity, the 6T70/75 has the capability to transfer more torque to the drive wheels, particularly in all-wheel drive applications. It also helps vehicles, such as crossovers like the Outlook, to feel even livelier at lower speeds, particularly at launch or when pulling away from a stoplight.

The 6T70/75 offers the capability of driver shift control (DSC), which allows the driver to use tap-up/tap-down shifting to select the desired gear for specific road conditions, such as driving up a steep hill. A sophisticated transmission electro-hydraulic control module (TEHCM) is mounted inside the 6T70 and 6T75, reducing vehicle complexity. Similar to the control system used in the six-speed Hydra-Matic rear-wheel drive transmissions, the TEHCM offers improved quality through its hard-wired connections. The unit is located entirely within the transmission and operates while bathed in transmission fluid. Locating the controller internally facilitates the modular design and assembly strategy while also shielding the unit from the outside environment.

The 6T70/75 was co-developed with Ford Motor Co. Co-development of the transmission allowed it to reach production in less time and enabled each company to reduce development costs by as much as 50 percent. A common on-axis design and many common components are shared between GM and Ford Motor Co. The controls, calibrations and operation of the transmissions are unique to each company.

New 6L50 RWD and AWD six-speed

A new Hydra-Matic 6L50 six-speed transmission debuts in certain 2007 Cadillac STS rear- and all-wheel drive performance sedans and the V-8-powered SRX crossover SUV. The 6L50 is the second model of four new variants in the RWD six-speed transmission family. The 6L50 is designed with the same modular flexibility as the larger 6L80 and is fully compatible by using the same advanced electronic controls. As with the 6L80, the 6L50’s gearset configuration enables the same 6.04 wide overall ratio.

As with other GM six-speeds, the 6L50 delivers smaller steps between gears, enabling the vehicle to quickly find the best gear. A higher numerical first gear delivers strong acceleration from a standstill and two overdrive gears enable improved fuel economy through lower engine rpms at cruising speed. Also, the lower rpm achieved with the sixth gear reduces engine noise and vibration on the highway.

The 6L50 also uses the Driver Shift Control feature, which allows the driver to shift the transmission like a clutchless manual gearbox. Also, the transmission is calibrated to override the automatic gear selection during closed-throttle, high-lateral acceleration maneuvers, rapidly downshifting with nearly synchronous engine speed matching for quick power-up when the throttle is reopened. This gives the feel of a manual transmission during deceleration. Electronic safeguards prevent over-revving.

6L80 RWD six-speed

The Hydra-Matic 6L80 six-speed automatic transmission was the first of four variants in the rear-wheel drive transmission family designed with modular flexibility and compatibility with advanced electronic controls. It also features clutch-to-clutch operation, manual range selection and an integrated 32-bit electro-hydraulic controller. It debuted in 2006 on the Cadillac XLR-V, STS-V and Chevrolet Corvette, where it is offered with paddle-shift control.

The 6L80 also is tailored for the heavy-duty requirements of SUVs and trucks, and is offered on GM’s 2007 full-size SUVs equipped with the Vortec 6.2L V-8, such as the GMC Yukon Denali and Cadillac Escalade. In all applications, the 6L80 has a wide, 6.04:1 overall ratio – including two overdrive gears – that helps deliver up to 7 percent improved 0 – 60 mph performance and up to 4 percent improved fuel economy.

The 6L80’s six forward gears have smaller “steps” between them, which bolsters both performance and the feeling of smoothness. The smaller steps also enable a steep, 4.02:1 first gear, which provides an improved-performance launch feel. And with two overdrive gears, engine rpm is reduced by approximately 9 percent at 60 mph – a reduction of about 1,350 rpm.

A 32-bit electro-hydraulic control module optimizes transmission performance according to a variety of vehicle inputs, while also enabling features including tow/haul mode, auto grade braking and manual range selection. The controller is integrated within the transmission.

Tow/haul mode is a driver-selectable feature of the 6L80 that reduces shift busyness when towing or hauling a heavy load. The feature is complemented by manual range selection, which allows the driver to block out upper gears and select desired gears for unique driving conditions, such as towing on a steep grade. The manual range selection feature increases the feeling of control by holding the gear pre-selected by the driver. Electronic safeguards prevent the transmission from being shifted in a manner that could cause engine damage or loss of vehicle control. Auto grade braking is available when the tow/haul mode is selected and the transmission is not in the range selection mode.

SPECIFICATIONS: HYDRA-MATIC 6T70 / 6T75

 

2007 6T70 ( MH2 )

2007 6T75 MH6 MY9

Type:

Six speed front-wheel-drive, electronically controlled, automatic overdrive transaxle with an electronically controlled torque converter clutch.

Six speed front-wheel-drive & AWD, electronically controlled, automatic overdrive transaxle with an electronically controlled torque converter clutch.

Engine range:

4.0L

4.6L

Maximum engine torque:

280 lb-ft (380 Nm)

301 lb-ft (406 Nm)

Maximum gearbox torque:

462 lb-ft (515Nm)

463 lb-ft (515Nm)

Gear ratios:

First

4.48

4.48

Second

2.87

2.87

Third:

1.88

1.88

Fourth:

1.47

1.47

Fifth

1.00

1.00

Sixth

0.74

0.74

Reverse:

2.88

2.88

Final drive ratio:

2.77

3.16:1

Maximum shift speed:

1-2: 6800 rpm

1-2: 6800 rpm

2-3: 6800 rpm

2-3: 6800 rpm

3-4: 6800 rpm

3-4: 6800 rpm

Maximum validated gross vehicle weight:

4850 lbs

6384 lbs

Shifter positions:

P, R, N, M

P, R, N, M

Case material:

die cast aluminum

die cast aluminum

Shift pattern:

4 VBS Solenoids

4 VBS Solenoids

Shift quality:

Variable Bleed solenoid

Variable Bleed solenoid

Torque converter clutch:

258 mm

258 mm

Converter size:

246 mm (reference) (diameter of torque converter turbine)

246 mm (reference) (diameter of torque converter turbine)

Fluid type:

DEXRON® VI

DEXRON® VI

Transmission weight:

wet: 102 kg

wet: 104 kg

Fluid capacity (approximate):

9.0 L

9.0 L

Bottom pan removal:

NA

NA

Pressure taps available:

line pressure

line pressure

Transfer design:

three-axis design

three-axis design

Assembly sites:

Warren , Mich.

Warren , Mich.

Applications:

Saturn Aura

Saturn Outlook

Pontiac G6

 

SPECIFICATIONS: HYDRA-MATIC 6L50

2007 Hydra-Matic 6L50 (MYB)

Type:

Six speed RWD / AWD, electronically controlled automatic overdrive transmission with torque converter clutch. Clutch-to-clutch architecture, with integral Electro / Hydraulic Controls Module

Maximum engine power:

315 bhp (235 kW)

Maximum engine torque:

332 lb-ft (450 Nm)

Maximum gearbox torque:

480 lb-ft (651Nm)

Gear ratios:

MYB

First:

4.06

Second:

2.37

Third:

1.55

Fourth:

1.16

Fifth:

0.85

Sixth:

0.67

Reverse:

-3.2

Maximum shift speed

7000 rpm

Maximum Validated Weights: ( Target )

GVW: 6613 lb (3000 kg), GCVW: 12505 lb (5672kg)

7-position quadrant:

P, R, N, D, X, X, X ( X = available calibratable range position )

Case description:

3-piece ( Bell, main, extension)

Case material:

die cast aluminum

Shift pattern:

(2) Three-way on/off solenoids

Shift quality:

Five variable bleed solenoid

Torque converter clutch:

Variable Bleed Solenoid ECCC

Converter size:

258, 280mm (reference)

Fluid type:

DEXRON® VI

Fluid capacity: w/258mm converter

TBA

Transmission weight: w/258mm converter

wet: 85-90 kg (187-198 lb) estimated

Pressure taps available:

line pressure

Assembly sites:

GMPT Strasbourg, France

GMPT Ypsilanti, Mich.

Applications:

Cadillac STS

Cadillac SRX

Available control features:

Multiple shift patterns (selectable or adaptive)

Driver Shift Control (Tap Up / Tap Down)

Enhanced Performance Algorithm Shifting (PAS II)

Next-generation tow / haul mode

Engine torque management on all shifts

Altitude and Temperature Compensation

Adaptive shift time

Neutral idle

Reverse lockout

Automatic grade braking

Additional features:

GM Oil Life System

OBDII / EOBD

Integral Electro/Hydraulic Controls Module -- TEHCM

Control Interface Protocol - GMLAN

SPECIFICATIONS: HYDRA-MATIC 6L80

2007 Hydra-Matic 6L80 (MYC) 

Type:

Six-speed RWD / AWD, electronically controlled automatic overdrive transmission with torque converter clutch. Clutch-to-clutch architecture, with integral Electro / Hydraulic Controls Module

Maximum engine power:

413 bhp (308 kW)

Maximum engine torque:

430 lb-ft (583 Nm)

Maximum gearbox torque:

664 lb-ft (900 Nm)

Gear ratios:

MYC

First:

4.03

Second:

2.36

Third:

1.53

Fourth:

1.15

Fifth:

0.85

Sixth:

0.67

Reverse:

-3.06

Maximum shift speed

6500 rpm

Maximum validated weights:(target )

GVW: 8600 lb (3901 kg), GCVW: 14000 lb (6350 kg)

7-position quadrant:

P, R, N, D, X, X, X (X = available calibratable range position )

Case description:

Three-piece ( Bell, main, extension)

Case material:

die cast aluminum

Shift pattern:

(2) Three-way on / off solenoids

Shift quality:

Five variable bleed solenoids

Torque converter clutch:

Variable Bleed Solenoid ECCC

Converter size:

300 mm ( reference )

Fluid type:

DEXRON® VI

Fluid capacity: w/ 258 & 300mm converter

258 mm: 9.7 L (8.22 kg), 300 mm: 11.9 L (10.1 kg)

Transmission weight: w/ 258 & 300mm converter

258 mm: Wet: 94-96 kg (207-211 lb)

  300 mm: Wet: 102-104 kg (225-229 lb)

Pressure taps available:

line pressure

Assembly site:

GMPT Ypsilanti, Mich.

Applications:

Chevrolet Corvette

Cadillac XLR

Cadillac XLR-V

Cadillac STS-V

GMC Yukon Denali

GMC Yukon Denali XL

Cadillac Escalade

Cadillac Escalade ESV

Cadillac Escalade EXT

Available Control Features:

Multiple shift patterns (selectable or adaptive)

Driver Shift Control (Tap Up / Tap Down)

Enhanced Performance Algorithm Shifting (PAS II)

Next-generation tow / haul mode

Engine torque management on all shifts

Altitude and temperature compensation

Adaptive shift time

Neutral idle

Reverse lockout

Automatic grade braking

Additional Features:

GM Oil Life System

OBDII / EOBD

Integral Electro/Hydraulic Controls Module – TEHCM

Control Interface Protocol - GMLAN

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Any news of them adding this to the rest of the 900 suv's...Tahoe yukon pick up???

I heard for the MY2008 if production capacity is up to speed on the transmissions.

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I heard for the MY2008 if production capacity is up to speed on the transmissions.

yea i heard the same... by 2008, all the full size stuff should be 6 speeds

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Screw the trucks...when are we going to start seeing these in more of the sedans to help them compete(finally) against higher end and import models?

In my opinion GM must have the 6-speed in the following vehicles by MY 2008.

Impala(and make it RWD), same for Monte Carlo SS

Lucerne

LaCrosse

Saab 9-5 at least(9-3 would be nice too)

Grand Prix(G8?)

Then I could at least begin to consider actually purchasing some of these vehicles rather than looking elsewhere for my next purchase.

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Screw the trucks...when are we going to start seeing these in more of the sedans to help them compete(finally) against higher end and import models? 

In my opinion GM must have the 6-speed in the following vehicles by MY 2008. 

Impala(and make it RWD), same for Monte Carlo SS

Lucerne

LaCrosse

Saab 9-5 at least(9-3 would be nice too)

Grand Prix(G8?)

Then I could at least begin to consider actually purchasing some of these vehicles rather than looking elsewhere for my next purchase.

The 9-3 2.8T already has a six-speed auto.

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Screw the trucks...when are we going to start seeing these in more of the sedans to help them compete(finally) against higher end and import models? 

In my opinion GM must have the 6-speed in the following vehicles by MY 2008. 

Impala(and make it RWD), same for Monte Carlo SS

Lucerne

LaCrosse

Saab 9-5 at least(9-3 would be nice too)

Grand Prix(G8?)

Then I could at least begin to consider actually purchasing some of these vehicles rather than looking elsewhere for my next purchase.

trucks are gm's bread and butter

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I'm just not seeing the fuel economy benefit that they keep talking about. The Saturn Aura midsize with the 3.6 DOHC and new 6 speed automatic is rated at only 18/27 which is way behind some newly introduced models and flat out embarressing. The low tech pushrod 3500 and 4 speed automatic are rated higher at 20/30 so i'm not seeing the extra efficiency in the new 6 speed trans. Lets hope that it proves far more efficient in other applications.

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Anyone catch the comment about 4.0L engine? What's that for? When's it coming? V6 or V8???

B.

Yeah a 4.0L are they bringing back the old Aurora V8? If so, then this would be amazing. If they could bring it in with more HP than the 3.6DI engine this would make for a great mid level V8. I still think the Northstar should move up in displacement.

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Sorry, didn't realize Saab already had the 6-speed. Don't recall it being as big a conversation as when the Aura got it and hence this topic being started.

And to go back to my truck comment...they may be GM's bread and butter, but if they want the rest of the meal someday, they need to expand their sights.

To me they are losing big in the family sedan/midsize categories and this is where I see the need to step up to the 6-speed.

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I'm just not seeing the fuel economy benefit that they keep talking about. The Saturn Aura midsize with the 3.6 DOHC and new 6 speed automatic is rated at only 18/27 which is way behind some newly introduced models and flat out embarressing. The low tech pushrod 3500 and 4 speed automatic are rated higher at 20/30 so i'm not seeing the extra efficiency in the new 6 speed trans. Lets hope that it proves far more efficient in other applications.

the reason for that, is because DOHC's are less efficent then push rod, they have more moving parts and more rotational mass... also they can be designed to be more powerful, again less efficent...

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Sorry, didn't realize Saab already had the 6-speed.  Don't recall it being as big a  conversation as when the Aura got it and hence this topic being started. 

And to go back to my truck comment...they may be GM's bread and butter, but if they want the rest of the meal someday, they need to expand their sights. 

To me they are losing big in the family sedan/midsize categories and this is where I see the need to step up to the 6-speed.

That's because the 9-3's six-speed is supplied by Aisin AW, as is the 6-speed auto in the Ford Five Hundred.

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Or at least GM should be offering more manual transmissions regardless.

*Cough* Like in the 4 cylinder G6 that should be allowed the available equipment of upper V6 models.

Or the Aura.

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I heard for the MY2008 if production capacity is up to speed on the transmissions.

so will we have to wait till the end of calander year 07 to see the 6 speeds in the burb and Tahoe?

what do ya'll think the likely-hood of a 6.0 with a 6 speed will be in a 1/2 ton 4X4 burb and tahoe will be? gas mialage?

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