6 Speed With 5.3l - What Mpg?

TxTruckMan · April 22, 2008

What do you guys think the MPG will be for the 2009 trucks and SUVs with the 6 speed transmissions? I'm looking at getting a Tahoe or Crew Cab Silverado next year and am just curious.

Right now they're listed as 15/19 for the Silverado, and 16/21 for the Tahoe - both 2WD. Any guesses?

cc1999 · April 22, 2008

What do you guys think the MPG will be for the 2009 trucks and SUVs with the 6 speed transmissions? I'm looking at getting a Tahoe or Crew Cab Silverado next year and am just curious.

Right now they're listed as 15/19 for the Silverado, and 16/21 for the Tahoe - both 2WD. Any guesses?

I would expect about a 15-20% increase. I get 14-16 with my 07' 4x4 Suburan with the 5.3 4 speed auto. I am hoping when I turn in my 07 for a 09 that I will get about 15-18 out of the new 09, with the same options just adding the 6 speed.

vranasaurus · April 22, 2008

What do you guys think the MPG will be for the 2009 trucks and SUVs with the 6 speed transmissions? I'm looking at getting a Tahoe or Crew Cab Silverado next year and am just curious.

Right now they're listed as 15/19 for the Silverado, and 16/21 for the Tahoe - both 2WD. Any guesses?

I would expect about a 15-20% increase. I get 14-16 with my 07' 4x4 Suburan with the 5.3 4 speed auto. I am hoping when I turn in my 07 for a 09 that I will get about 15-18 out of the new 09, with the same options just adding the 6 speed.

I doubt you'll see anwyhere close to a 15% to 20% increase in fuel economy. The overdrive gear in the 4 speed is .70:1 and the overdrive gear in the 6 speed is .67:1. The difference being that the 6 speed has an additional OD gear (5th at .85:1) that is most beneficial when towing or hauling a load. Otherwise running the two on the highway is about the same.

I love the 6 speed in my truck it drives nice but it doesn't do anything for fuel economy.

HawkeyeOC · April 22, 2008

Probably not much more than a 1 mpg difference city/hwy. A 15-20% increase I would think is a little optimistic. That puts it near hybrid territory

cc1999 · April 22, 2008

Correct this if its wrong but its my understanding that a hybrid is useless on the hyway as far gaining anything, other than what GM did with Aero dynamics and the light weight wheel and tire combo they are running on the hybrid pkg, that might help hyw numbers some.

My dad picked up 2-3mpg going from the GMT800 AWD Escalade to the GMT 900 AWD Escalade. I attributed that increase to the 6 speed vs the 4 speed in his old one. Will have to wait and see but

I only projected 1mpg in town and 2 on the highway over what I am geting with the 4 speed I have now. I am not sure how that is being optomistic. I would hope 2 more gears can deliver that much at least.

HawkeyeOC · April 22, 2008

Correct this if its wrong but its my understanding that a hybrid is useless on the hyway as far gaining anything, other than what GM did with Aero dynamics and the light weight wheel and tire combo they are running on the hybrid pkg, that might help hyw numbers some.

My dad picked up 2-3mpg going from the GMT800 AWD Escalade to the GMT 900 AWD Escalade. I attributed that increase to the 6 speed vs the 4 speed in his old one. Will have to wait and see but

I only projected 1mpg in town and 2 on the highway over what I am geting with the 4 speed I have now. I am not sure how that is being optomistic. I would hope 2 more gears can deliver that much at least.

Hybrids are pretty much useless at saving gas on the highway, but edmunds saw a 25% overall increase on the Hybrids

GMT-800 Escalades used a 6.0L iron block engine

GMT-900 Escalades use a 6.2L all aluminum engine with Variable Valve Timing and yes, the 6spd and added DOD for '08

but, the 800s and the 900s are two completely different trucks

Credit for your 900s increase can go to the 6spd as well as a better engine, aerodynamic improvements.

omegafiler · April 22, 2008

Correct this if its wrong but its my understanding that a hybrid is useless on the hyway as far gaining anything, other than what GM did with Aero dynamics and the light weight wheel and tire combo they are running on the hybrid pkg, that might help hyw numbers some.

My dad picked up 2-3mpg going from the GMT800 AWD Escalade to the GMT 900 AWD Escalade. I attributed that increase to the 6 speed vs the 4 speed in his old one. Will have to wait and see but

I only projected 1mpg in town and 2 on the highway over what I am geting with the 4 speed I have now. I am not sure how that is being optomistic. I would hope 2 more gears can deliver that much at least.

Hybrids are pretty much useless at saving gas on the highway, but edmunds saw a 25% overall increase on the Hybrids

GMT-800 Escalades used a 6.0L iron block engine

GMT-900 Escalades use a 6.2L all aluminum engine with Variable Valve Timing and yes, the 6spd and added DOD for '08

but, the 800s and the 900s are two completely different trucks

Credit for your 900s increase can go to the 6spd as well as a better engine, aerodynamic improvements.

Exactly. And don't forget, any gains you may or may not see won't last long with the way gas prices are going. It amazes me how many people buy a big gas guzzler, gas goes up a $.50, and then they freak out and start wondering how to get better MPG or end up selling.

HawkScot · April 23, 2008

Don't overlook tire sizes and rear end gears.

music · April 23, 2008

GM's published statement is that overall fuel economy will increase by about 4%. If you get 18 now, you'll get 18.8 with the 6-sp. The six speed will help with acceleration and, at least for the larger 6.x engines, with towing as well. I am not convinced that a 6-sp mated to the 5.3L will provide optimum gearing for 4k+ lb towing. That's another thread...

2017HD · April 23, 2008

If you keep the same rear end gears then hy MPG will be about the same - however when you start using the truck for towing or hauling the extra low 1st and broad overall ratios make it a real dream. Being able to have an OD and a near 1:1 that can be used for towing are very good. O have a 2500 HD with the 6.0L and 4.10 gears and tow a 6000 lb TT I mostly use 4-5 and 6th gears when towing.

a_guerrajr · April 23, 2008

What do you guys think the MPG will be for the 2009 trucks and SUVs with the 6 speed transmissions? I'm looking at getting a Tahoe or Crew Cab Silverado next year and am just curious.

Right now they're listed as 15/19 for the Silverado, and 16/21 for the Tahoe - both 2WD. Any guesses?

I would expect about a 15-20% increase. I get 14-16 with my 07' 4x4 Suburan with the 5.3 4 speed auto. I am hoping when I turn in my 07 for a 09 that I will get about 15-18 out of the new 09, with the same options just adding the 6 speed.

Is it really worth losing all that depreciation to gain 1-3 MPG ?

I was thinking of doing the same, but from the sounds of it, it seems like it might be a bad idea.