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2009 GM 6.0 gas with 6 speed auto?

A

AbnRangerM7

Active member
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.
 
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
 
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
Click to expand...

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.
 
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.
Click to expand...

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
 
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
Click to expand...

The truck has a booklet for an allison transmission in the glove compartment :confused:
 
Dogmeat said:
The truck has a booklet for an allison transmission in the glove compartment :confused:
Click to expand...

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.
 
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.
Click to expand...

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.
 
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?
 
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.
 
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.
 
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.
 
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 :D
 
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