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2002 Chevy 2500Hd with 8.1 & Allison, best setup so far

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2002 Chevy 2500Hd with 8.1 & Allison, best setup so far


Old 06-20-2012, 11:38 PM
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I know they used it untill 2006. 2007 might depend on what vehicle you are looking at.

I have a 2004 Chevy Suburban with 8.1L - 3.73 and 130k miles on it. Driving normal on highway at 70 to 75 I get a solid 14 mpg. Towing a 32' travel trailer that weighs in right at 10,000 lbs I get 8 to 8.2 mpg and you forget it is back there unless you are in hilly terrain, then the transmission shifts and you remember why. Ride is also great for a 3/4 ton truck. I bought mine because it has the cloth seats with the 60/40 front bench so it can seat 9. We have 5 kids and are Foster parents, so we never know when we may need the seating. Great truck, really impressive.

Typical GM, get something that works well and people like, so you have to drop it or change it. Oh, and mine will use a quart of oil around the 2,000 mark also.

never new they were available in the vans, might have to look into one of those.

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Old 06-21-2012, 12:00 AM
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I think the 2007 Classic's still came with it, I know the 2007 New Body style it was either the 6.0 or the Dmax.
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Old 06-21-2012, 08:20 AM
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The 8.1 and Allison are a great combo. A Hypertec tuner will give you a little more power in the over 4000 rpm range. I have a 2004 3/4 ton avalanche- 12 mpg around town, 14 hiway, 8 towing the Chris Cat. I didn't want a diesel when I bought the truck and it is built on the suburban chassis.

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Old 06-21-2012, 08:23 AM
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Mine is the ext cab version with black leather interior. wow does that ever pop when you open the door. Also head room is unreal verses ford and dodge. For the money, this is it so far in my eyes. They even made a 4*4 van with this setup also, killer grocery getter, or soccer van for 12 kids.
Thanks for the input. Makes me feel even better now.

Last edited by B38; 06-21-2012 at 10:34 AM.
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Old 06-21-2012, 08:50 AM
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I have 230,000 miles on my 2001 C3500 GMC club cab, 8.1 with allison transmission. oil is changed every 3000 miles, amsoil is used in the transmission, as well as the differential. besides the truck looking like a 2001 model, it is in great shape. would NOT trade it in as replacement cost is out of control.
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Old 06-21-2012, 08:53 AM
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Can you get the Allison with a gas engine now?
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Old 06-21-2012, 08:53 AM
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I loved everything about mine except the mpg.

Last edited by Sin_or_Swim; 06-21-2012 at 09:07 AM.
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Old 06-21-2012, 09:16 AM
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Originally Posted by Sin_or_Swim View Post

I loved everything about mine except the mpg.

Here is a video of my brother (6.0) and I, he only won because he waited for me to break lose.


Do that again....drop air press in rear tires to 20 psi, you win.

I have 01 2500 HD CC with the 496 Allison, love the truck, s hitty gas mi but it doesnt matter as it's not a daily driver, just pulls my boat or race car, sits there otherwise. If you roll into it and stay out of the torque management it will haul azz. Some guys at the Diesel Place get a custom tune that gets around the torque management and they will really fly. Mine has a cracked exhaust manifold and sounds s hitty when cold, anyone else have that prob?
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Old 06-21-2012, 10:00 AM
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I have that in a 05 dually

Got 8.2 towing a 42 Fountain from Chicago to Louisiana and back,,,, 2000 miles for the Tickfaw 200

Not my DD so I dont care about the MPG

Had a custom tune and it pulls anything I want

Wish they still made it as I would like to get a newer truck
Attached Thumbnails 2002 Chevy 2500Hd with 8.1 & Allison, best setup so far-dually-wheels.jpg  
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Old 06-21-2012, 10:39 AM
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What's nice about this engine is the torque peaks at 3200 RPM and the HP at 4200. I cruise on the freeway at 2500 RPM but when I see a good hill coming I drop down to 5th and run the motor up to 3200 and it pulls right up the hill with a load. If it's not enough, I have plenty more RPM's & HP until I have to go down another gear. I've never had any reason to wind this motor up to get power like the smaller 6.0's. It's just a nice lazy BBC with plenty of power to pull.

Getting rid of this motor in the HD trucks was a stupid move on GM's part. I'd love to buy a new truck but I don't want a diesel so I've maintained my 2001.

Last edited by RickSE; 06-21-2012 at 10:45 AM.
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