Bought new, Loved everything, wanted to keep until wheels fell off. Then, the rear-end fell out of my dream! At 96,000 rear-end had to be rebuilt. 38,000 later, pulling a 12 ft trailer, rear-end went out again. Replaced with a rebuilt one. Just a few thousand miles & I can hear the familiar hum again. Many Avalanches must not have this problem, but if you got one with a faulty rear-end, it must be faulty from the factory, and can't be corrected. I'm now figuring, any rebuilt you buy is one of the faulty ones that can't be really fixed. So I guess I'm in a fix, unless I get one off a wrecked truck & pray it's from a truck with a good rear-end. But this is spending around $1100 to $1400 everytime.
Please do your research, before you buy an Avalanche. Consumer Reports rates all years, but 2012, as worse/much worse than average. We bought our LTZ new in 2007 and currently have 97,000 miles on it. I was pulling my camper home last year, from a camping trip, when, about 6 hours from home, the transmission failed (87,000 miles on the vehicle). Fortunately, I found a Chevy dealer close by and they were amazing (wish they were closer to home!). I've had most all of the problems that Consumer Reports and owner reviews have detailed. Power steering pump replaced; starter replaced; routinely replace TPMS sensors; back-up lights stay on sometimes, running battery down; currently having intermittent problems with the all-wheel drive, stability control, and traction control systems (don't know what's going on there); and myriad of electrical problems. I contacted Chevrolet's Customer Assistance Center and got the standard response that it's probably abuse and poor maintenance, completely discounting Consumer Reports' and owners' reviews. My local mechanic, I refuse to go to a Chevy dealer - don't trust them, suggests that I unload the Avalanche before anything else major happens. This is really sad, since I love the vehicle and hate to part with it. Like another reviewed said, it's truly a love/hate relationship.
Update 9/20/2016 - Got rid of this headache in March. Bought a new GMC Acadia and love it. It tows my camper better than the Avalanche and it's only a six cylinder. Hope it gives me better service! I bought a 10-year, 100,000-mile extended warranty, just in case!
I bought my '07 LT trim 6 months ago with 89k on the clock. It was a dealer maintained one owner truck. I've now got just under 100k on it. So far so good I guess?... Mine does "consume oil" like others say, I'm only about a quart low between oil changes. Recent repairs consist of the front passenger side caliper sticking, warping the rotor and busting the brake master cylinder. Costs about $600 for a new master cylinder, calipers, brake pads and rotors for the front of the truck. only one trip to a repair shop so far is acceptable, buying a higher mileage vehicle I came to expect to start replacing components. It rides great, the seats are comfortable, handles like an agile truck, even the stock stereo sounds good. Power is adequate, the 5.3 is a tad sluggish from a stop and on highway passing. I probably feel that way because I had test driven a Yukon Denali and Caddilac Escalade with the 6.2 before ultimately buying the Avalanche. The best benefit of this truck is the midgate, I needed cargo and people space and it's perfect for the job. I can carry my family in the cabin, and carry my equipment in the bed. Overall I'm satisfied, I would call it a "good" truck, however not a "great" truck. I'd recommend it if you need flexibility in carry capability. If you want one, make sure it has service records/history as it seems these will break down if not properly maintained. Lastly, anticipate that you will be making some repairs yourself.
Update 9/22/2016 At 104k the 2nd/4th shift band inside the transmission broke. $2000 transmission rebuild. 106k the oil pressure sending unit went out. $30 part and replaced myself. I'm less than pleased that the transmission went out so soon, my '97 Jeep Grand Cherokee's trans went out at 170k! I still like the truck, and I'm going to stick with it for now. If I catch any signs of potential drivetrain failure within the next year I'm going to get out of this truck ASAP.