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GMC Yukon Denali gets up to 22 mpg with new eight-speed automatic
Left Lane News
By Justin King
Thursday, Nov 6th, 2014

After making its debut in the Corvette Stingray, the Hydra-Matic 8L90 gearbox has continued to spread across GM's lineup. The extra gears help the Yukon Denali achieve an EPA highway estimate of 22 mpg for the two-wheel-drive variant or 21 mpg for the four-wheel-drive edition.

The 6.2-liter EcoTec V8 remains unchanged, delivering 420 horsepower and 460 lb-ft of torque, however the new transmission has been paired with a lower 3.23:1 rear axle ratio. The gearbox provides quicker shifts than the outgoing six-speed unit, with a new torque converter that promises smoother performance at low speeds -- particularly when towing or carrying heavy loads.

*Full Article at Link
 

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I saw this earlier, but was confused. Is this a revision of what it was listed when the 8-speed was first released? I vaguely remember the numbers staying the same for the 2wd and the 4wd was the same as the 2wd. I looked for an earlier release in the search but couldn't find it.

These numbers are better than the Silverado with the same powertrain. Maybe a revision in it's numbers are coming?
 

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Our 2015 Yukon XL averaged 22 mpg on a recent road trip that was 750 miles roundtrip, and it only has the 5.3 liter engine. This is pretty impressive for the 6.2 liter. Meanwhile, Ford Expeditions with the EcoTurd is getting 18 mpg? HA! Ford sucks.
I'd be very careful comparing economy figures from different sources, the 5.3 on cruise puts up great numbers indeed but I would expect the new 6.2 w/8-speed to be even better in that same light cruise situation.

The Ford I don't know but it's rated the same as the 6.2 8/speed so maybe under light running, it gives the same. Problem is the turbo power comes in quickly and it only takes small throttle changes to affect economy. I don't think respective buyers would be disappointed with whatever vehicles they choose..
 

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So, what are we looking at when it goes into the regular trucks?
 

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Those do look like good numbers.

I have a V6 STS and got 23 MPG on a recent road trip.
 

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:tup:: Gotta give it to GM on this, great combo of power/performance and MPG's. Still not a fan of the center stack or the third row, but I have no qualms with the engine/drive train.
 

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The big negative on these SUVs seems to be that the accelerator has long travel,and that the 6 spd is always grabbing a higher gear, making the truck feel a little underpowered. Hopefully GM has done some different tuning on the 8 spds.
 

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Trying to find what axle ratios are available for the 2015+ 6.2L V8s... The 3.23 can't be the only one... right?
 
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