8.1L Chevrolet Avalanche 2500

That's about right....our TT is 9000 loaded and we get about 7mpg towing 65-70 mph on the interstate, as high as 13 unloaded with a tailwind....

BUT make no mistake that 65-70 is up some good grades. The machine will tow, but you pay for the privilege.....

I had an 8.1 Burb for a year. Used it to tow my 7000ish pound boat. I bought it used with about 115000 on the clock. Lots of interior rattles, and it would rather tow on the interstate in 3rd instead of 4th. Which is fine except as mentioned for the MPGs.

Over about 20,000 miles, its average was 9.84. Highest it ever got was 13, and the lowest (several tanks when towing at 70 MPH) was 7 MPG.

There tends to be low mileage trucks around here. Just have to keep looking around. There are bargains to be had if you keep your ear to the ground. I had completely forgot they made these.

I believe this is a 2006. Its a 1-ton regular cab with the 8.1L and 6 speed hydra-matic.

The truck, trailer and snowcat weigh 27,000 lbs and this is about all this truck is used for. It has just over 60,000 miles and still doesn't use any oil and we have not has a single engine or transmission problem.

The truck works its guts out towing the cat and gets about 4.5-5 mpg towing but that's a lot of weight. I think the CGVW is 22,000 lbs.

We tow this cat from 6000 up to about 8500 ft.

So far its been pretty impressive.

My cousin had a truck with the 8.1, he towed a giant race car trailer with it, he also said it was a tow monster, but around 4-5 mpg in a head wind @ 75mph.

AutoTrader found 3 in the US, 2 in IL, one in Ft Walton Beach FL. The 8th character of the VIN should be a "G" to indicate the big block.

These all look very clean at 98k, 125k, and 134k miles.

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If you like a lift kit and cow catcher, here's 2 in OH on Cars.com:

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I had a 2001 Chevy 2500 with the 8.1 strapped to the Allision with either the 4.10, if not mistakened, it was a towing animal.. I towed a 5er with a GVW of 12K and towed in the mountains of NC, TN, WV and TN... easily towed it. BUT, it loves gas stations.. Great truck, engine and tranny combo!

Jim

The only ones worth buying these days are the ones where Grandma only used it to tow the travel trailer to church on Sundays.

Big Block Suburbans are hard to find, the newest one is now 10 years old....feel free to PM with any questions if I can help.

BurbMan wrote:
Rear axle ratio has no effect on payload, it's 8600 lbs GVWR on all 2500's, giving you about 2000 lbs of payload capacity.

Towing limits with the 8.1 are 10,500 and 17,000 GCWR for the 3.73 axle and 12,000 with 19,000 GCWR for 4.10 axle.

The 8.1 was available in the Suburban/Avalanche from 2001-2006. 2004+ got a few nice upgrades including steering wheel audio controls, touch screen stereo with nav option and digital OnStar. 2001-2003 1/2 models had analog OnStar which is not upgradable and no longer works since the FCC gave carriers the OK to discontinue support for analog service 10 years ago.

Sub/Avy's with the 8.1 also came with AutoRide (RPO Z55), which on the 2500's is NOT load leveling but magnetic ride control. Shocks are $250 EACH unless you bypass the AutoRide System and install regular shocks (I have KYBs).

Also check the brake/fuel lines, GM vehicles from this era have uncoated steel lines, and if the truck has seen any winters one or more lines is probably ready to rust through. Classic Tube sells full sets of brake/fuel lines in pre-bent stainless.

Right now I have 175k on my truck and the motor has never been opened, not even for valve cover gaskets. Seems like I've changed everything connected to the motor but the 8.1L runs strong.

If you're looking to buy one of these, I'm happy to help with any specific questions. I'm the original owner on mine and I also have the factory repair manuals. I started looking at new trucks a few years ago, but honestly I like the SUV body for the 3rd row seating capability. That, and pretty soon trucks are going to be like boats....so expensive that the average guy will only be able to afford a used one.

I have a 04 bourbon with a 5.3. Really like it. I forgot that one could get a 8.1 in a surburban. I'll start looking around for one of those. I have a 13 duramax, but I really like gas motors better-more familiar with them. Thanks