Chevy 8.1 Liter

[Anonymous-0]

Just wondering if anyone out there has had any experience with a Chevy or GMC truck with the 8.1 liter engine. Just wondering what kind of milage they got and any other pros and cons. And also when they quit putting these motors in the those trucks. Thank You in advance.

 

[Matt Weltz]

2006 was the last year of them I believe and the only year you could get one with the Allison 6 speed. They are an awesome motor if you are doing alot of heavy pulling. Tons of torque! My dad has one in his 2003 2500HD and we have easily pulled 30,000lbs with on the interstate. His truck is 4x4 with 4.10 rear end and the Allisone 5spd. He gets around 12MPG empty and anywhere from 5-10MPG pulling depending on the speed, weight and road. No trouble with his other than the head gaskets weap a little which is typical of GM big blocks.

 

[rustyfarmall]

I've got the 8.1 with a six speed manual in my 2001 K3500 dually. Fuel mileage ranges from a low of 8 to 10 mpg towing and 11 to 14 empty.

 

[fort67]

Hope this helps. Have a close freind that bought one new in 2002 4 wheel drive. He has 240,000 plus miles and uses it for everything. Motor runs like a top and the original Allison transmission. Does get serviced at regular intervals. Does use a quart of oil every 800-1000 miles. Even at new it used a quart every 1500. It's been a great reliable truck.

 

[mkirsch]

I picked up a 2002 Chevy dually this summer with the 8.1L and Allison transmission.

SWEEEEEET truck.

Tons of power and torque.

I love driving it, but it only gets about 9MPG with my camper and trailer.

12MPG empty around town. 14MPG or so on the highway.

Uses a little oil. About a quart in 1500 miles. Everything I've found says that's normal. Engine puts off so much heat that it atomizes the oil and blows it out the PCV valve. A 180 degree thermostat and Mobil 1 cuts the consumption down to a dull roar.

 

[luv2wrench]

I work as a GM diesel and transmission monkey. The 8.1 is an awesome power plant. They use oil which is normal and have pistion slap when started cold that goes away. (4.25 bore and 4.37 stroke) 496 cubes that pull like crazy. The best year of one you can get is a 06 or 07 CLASSIC body style. (not the new body for 07) The 06 and 07 years have the 6speed allison. The 5 and 6 speed transmission are the same basicly, the 6 speed just has a different valve body and applies another holding clutch to get one more gear. ) If you only pull once in awhile and not far, this is your baby.

Duramax's are great, but they are expensive to fix. I put a set of injectors in a 05 2500 LLY engine, 457.99 apiece. injection pump is 1000. labor intensive.

 

[Allis Fields]

I just bought a 2004 Chevy Avalanche 2500 with the 8.1 and the 4L85E trans. Towed my ex cab 4x4 pickup back home 500 miles. Hope it runs a long time.

 

[Shetland Sheepdog]

'04 Chev 3500 4x4 with 8.1 & Allison. I love it! Mileage has averaged 10.5 MPG for every mile driven. It's at 55,000 miles now, and I have never checked mileage on a specific trip or use, just total number of miles divided by total gallons used for a year (or similar records).
Dave