2009 GM 6.0 gas with 6 speed auto?

AbnRangerM7 · Jan 26, 2009

Has anyone gone from a GM 6.0 with the 4 speed to the newer truck with the 6 speed auto?
I currently have a 2002 Chevy 1500HD 6.0 (4 speed, Nelson's tune, Gibson exhaust, and CAI) I'm looking to get a new truck and wondered how much the 6 speed auto improved towing.

triedit · Jan 26, 2009

6.0

i have a 2009 6.0 with the six speed not only is the tranny way better for towing the motor in the 09 feels like it has 100 more horses i know it doesnt but it make your 02 feel like its got a six cylinder in it

Dogmeat · Jan 26, 2009

triedit said:
i have a 2009 6.0 with the six speed not only is the tranny way better for towing the motor in the 09 feels like it has 100 more horses i know it doesnt but it make your 02 feel like its got a six cylinder in it

I agree. I have a 2009 6.0 / Allison for a work truck ... only got about 3,500 miles on her so far, but I am definatley a lot happier with the 6-speed tranny than I was with the 4 speed ... For comparison my dad has a 1500 Vortec Max .... that truck is BEGGING for a 6 speed.

The gear ratios are simply just too far apart on the previous iterations of the 6.0L / 4L80/85e's ...

I still don't think it tows as well as my 8.1L, but it gets about 3 mpg better on the highway too. I've been getting 16 on the highway with it, 12 around town.

Truck is a 2009 GMC Sierra 2500HD, SBEC, 4.10 gears.

Seeder · Jan 26, 2009

Dogmeat said:
I agree. I have a 2009 6.0 / Allison for a work truck ... only got about 3,500 miles on her so far, but I am definatley a lot happier with the 6-speed tranny than I was with the 4 speed ... For comparison my dad has a 1500 Vortec Max .... that truck is BEGGING for a 6 speed.

The gear ratios are simply just too far apart on the previous iterations of the 6.0L / 4L80/85e's ...

I still don't think it tows as well as my 8.1L, but it gets about 3 mpg better on the highway too. I've been getting 16 on the highway with it, 12 around town.

Truck is a 2009 GMC Sierra 2500HD, SBEC, 4.10 gears.

Pretty sure it has the 6L80 trans not the allison. The ally is only avail with the oil burner in front of it, I think. The gasser 6 speed is gm's own trans, but still very stout from what I have heard,

-Seeder

theultrarider · Jan 26, 2009

The 8.1l gasser had the allison for sure...I beleive the new 6.0 with the 6speed is also the allison.

Dogmeat · Jan 26, 2009

Seeder said:
Pretty sure it has the 6L80 trans not the allison. The ally is only avail with the oil burner in front of it, I think. The gasser 6 speed is gm's own trans, but still very stout from what I have heard,

-Seeder

The truck has a booklet for an allison transmission in the glove compartment

Dogmeat · Jan 26, 2009

theultrarider said:
The 8.1l gasser had the allison for sure...I beleive the new 6.0 with the 6speed is also the allison.

Nod my 8.1L has the 5spd allison ...

RECREATIONAL IRON · Jan 26, 2009

Dogmeat said:
The truck has a booklet for an allison transmission in the glove compartment

From newcars.com:

Under the Hood
There are a couple of engine options on the heavy-duty Silverado. A 360-horsepower, 6.0-liter V-8 with 380 pounds-feet of torque, iron block/aluminum cylinder head and two valves per cylinder is mated to six-speed Hydramatic automatic transmission. A 365-hp, 6.6-liter diesel V-8 with 660 pounds-feet of torque, iron block/aluminum cylinder head and four valves per cylinder is mated to six-speed Allison automatic transmission.

I doubled checked on GM's site and when you build a truck you cannot even pick the allison as an option if the gas engine has been selected.

The 8.1 back in the day could be ordered with the allison, but the 2500 avalanche was only available with the 4 speed.

Bottom line: the only way to get an Allison is with the diesel and this is confirmed from two seperate sources.

Dogmeat · Jan 26, 2009

RECREATIONAL IRON said:
From newcars.com:

Under the Hood
There are a couple of engine options on the heavy-duty Silverado. A 360-horsepower, 6.0-liter V-8 with 380 pounds-feet of torque, iron block/aluminum cylinder head and two valves per cylinder is mated to six-speed Hydramatic automatic transmission. A 365-hp, 6.6-liter diesel V-8 with 660 pounds-feet of torque, iron block/aluminum cylinder head and four valves per cylinder is mated to six-speed Allison automatic transmission.

I doubled checked on GM's site and when you build a truck you cannot even pick the allison as an option if the gas engine has been selected.

The 8.1 back in the day could be ordered with the allison, but the 2500 avalanche was only available with the 4 speed.

Bottom line: the only way to get an Allison is with the diesel and this is confirmed from two seperate sources.

I could be mistaken but I'll check the window sticker on it tomorrow, I could have sworn it said that truck had the 6 speed allison too ... I'll double check.

2greentractors · Jan 26, 2009

I bought a 2007 and I am pretty certain it has a GM 6L90 transmission. It would be great if it got better mileage, but can tow anything.

AbnRangerM7 · Jan 27, 2009

Good info. I didn't know the new model 6.0 had 360 hp. My 2002 6.0 was only rated at 300 I think.
My 3 place enclosed trailer pulls easy (unless there is a head wind!) and I get 9-10 mpg going 75 mph.
The problem is when I'm towing my 35 foot travel trailer. It pulls hard so I usually have to leave it in 3rd gear and keep the speed below 65 mph. (It gets 8-9 mpg pulling the 7500 lb TT)

I know that some guys will say "Just get a Duramax and be done with it."
But, I kinda like having a gas truck and the ease of maintaining it.

What kind of weight are you guys towing with your new 6.0s and how does it handle it?

snosumitcsr · Jan 28, 2009

I have a 09 silverado for a work truck ,3.73 ,6 speed tranny ,363 HP ,headache rack and tool box. had an 05 with 4.10, 4 speed, 300 HP. the 09 gets 11.4 max so far, and the 05 got 12.6-13. Love the 09, lots of great improvements, but fuel mileage is horrible. even with higher gears and 6 speed Auto, it get 1 MPG Worse. Power is great, but i Would buy a used Diesel instead of this 6.0 Gas.

DaveB · Jan 28, 2009

Pretty sure the Allison is available behind the 8.1 in the Workhorse chassis still. (motorhomes)

Seeder · Jan 28, 2009

DaveB said:
Pretty sure the Allison is available behind the 8.1 in the Workhorse chassis still. (motorhomes)

Yup, and I think the 4500-5500 as well.

-Seeder

SaberKitty · Jan 28, 2009

My '08 GMC has the 6.2L (403 hp/417 lb-ft) with GM 6L80E six speed transmission.

Had two 6.0L (2001 and 2003) with the 4-speeds before this one and would never go back.

http://www.gm-trucks.com/forums/index.php?&autocom=registry&cmd=view_item&CID=1429

SaberKitty · Jan 28, 2009

Forgot to add - The really nice towing feature of the 6L80E transmission is the grade control that will hold a constant speed going down the mountain pass via engine braking. And similiarly, it downshifts agressively when slowing down for stoplights.

SilverGriz · Jan 28, 2009

I have the 2008 2500 HD version of the truck you are talking about. I love mine. The 6 speed transmission is a huge improvement over the 4 speed. It tows and shifts way better.

The Allison is only on the Duramax engine, however this 6 speed transmission acts and performs just as strong.

AbnRangerM7 · Jan 29, 2009

SaberKitty said:
My '08 GMC has the 6.2L (403 hp/417 lb-ft) with GM 6L80E six speed transmission.

Had two 6.0L (2001 and 2003) with the 4-speeds before this one and would never go back.

http://www.gm-trucks.com/forums/index.php?&autocom=registry&cmd=view_item&CID=1429

What other trucks is the 6.2L offered in besides the Denali?

Seeder · Jan 29, 2009

AbnRangerM7 said:
What other trucks is the 6.2L offered in besides the Denali?

The Caddy.

That engine is a monster but only comes in the high end rides.

When I had my 6.0 gas I had a Hypertech tuner and intake and I gained about 2 mpg's and a bunch more pulling power on the premium setting.

-Seeder

Dogmeat · Feb 9, 2009

ok, I stand corrected....

When I first read this on the window sticker of my work truck, I thought it meant allison ... but, what it says is:

"6 SPD HD AUTO TRANSMISSION"

Not "Allison", just 'HD'

guess I took that to mean allison.

I crawled under it too and it's definatley not the Allison

2009 GM 6.0 gas with 6 speed auto?

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