Purchased a used 2011 Chevy Avalanche with 87,000 miles one owner from a small dealership. After having the vehicle for about a week noticed it shuddering when pulling any kind of grade. Thinking it was some kind of misfire had all the plugs changed only to find that it also had an oil file problem with 1 of the cylinders. When the vehicle would shudder it was around 1500-2000 rpms. If I would give it more gas it made it past the 2,000 rpms and would shift with no problems. Needless to say the transmission is now toast as it gave out completely and needs replaced. No warning lights of any kind made me aware of a potentially serious problem. After reading more I am seeing that the transmission is something that GM has not fully taken care of as stated with older models. The transmission failed while driving on a major interstate roadway while nearing the top of a hill. It just went completely into neutral and would just rev the engine. The truck was carrying 3 adults and 2 children in car seats when this occurred. Thankfully we were able to get to the shoulder of the road safely. Currently the truck has 89,995 miles on it. I only put approximately 2000 miles on it since purchase.

- Mars, PA, USA

Active fuel management problem - oil passing the O-rings on the pistons which is causing the check engine light to come on and one cylinder out of the seven not working at all. It caused 2 new spark plugs to break

- Stroud, OK, USA

Service stabilitrac system indication comes on, with check engine light, and engine power reduced. Happens randomly, cannot find a "common cause" spent lots of money on PCM, BCM, memory seat module, battery cables, battery, brake light switch, etc. Etc. Dangerous condition when vehicle drops into power reduction mode.

- Port Charlotte, FL, USA

Traveling at 65mph in -25 degrees F, our check engine light and stabilink traction control lights came on. Dash display said vehicle would lose power and our engine shut-down. We pulled over on a snowy highway and read blogs and found our throttle body sensor would crack and fail at extreme cold temp. We started vehicle and it reset, but same problem happened within 5 miles. I found a auto-zone in princeton, Minnesota and bought part and replaced myself. As it was new years eve no GM assistance was available. GM tells us there was a service bulletin but they failed to notify us. Also told us a dealer would fix the problem for free, but failed to tell us how to get to a dealer with the engine shut down. I researched and found this problem common at cold temperatures. GM was dangerously irresponsible by not notifying us. They put us in a bad situation in extremely cold temps. I fail to see why this wasn't a recall when your vehicle basically shuts down. We could have easily been rear-ended or spun in a ditch. Thanks to blogs with no help from GM, I fixed the problem myself at extreme cold temp. GM will not cover my $190 for part, not counting stress, time and labor. How can they say they verified we received no notice, but would not cover our costs. I am sure there are many more drivers put in this situation. Thanks GM.

- Minocqua, WI, USA

Engine runs rough at idle when engine light, service stabilitrak light and traction control off lights all come on. Upon acceleration, only engine light remains on. Will repeat at lower idle.

- Adrian, MI, USA

At 40000 we noticed we were having issues with my Avalanche burning oil, when we asked the tech at Chevy he told me that was normal for the newer engines to burn oil, at 130,000 mile we started having problem with a spark plug fouling out, I read that this was directly related to the oil consumption problem. At 181,000 mile and only four years old we had to replace the engine after replacing the spark plug and wire 3 times this cost us $6847. I have read this is a constant problem with the 5.3 engines and could cause4 major accidents if the end up on a highway when they finally go out

- Becker, MN, USA

At times when the vehicle is slowing down/down shifting (more common when going up a grade) it will suddenly lunge forward (before coming to a stop) even with your foot on the brake. It seems to happen when downshifting from 2nd to 1st gear and sometimes it catches me off guard. This is a very dangerous situation especially when slowing down near people. I am always concerned that the vehicle is going to lunge forward and hit something or even worse someone. I hope NHTSA investigates this situation as other people have reported the same problem.

- North Providence, RI, USA

I was driving my truck at about 45 mph when the traction control light came on the dash and my truck suddenly went from 45mph to 20 mph and the motor began to miss fire and buck. If there would have been someone following me they would of hit me in the rearend due to the sudden slowing of my vehicle.

- Landisville, PA, USA

At @4000 miles on the vehicle the engine light came on. The dealership found that there was no oil in the engine and #1 spark plug was bad. They replaced the plug & oil. Again about another 4000 mile it did the same thing. They replaced the valve guide seals, that stopped the spark plug from going bad, but I have to put a quart of oil in it every 3,000 miles. A vehicle using synthetic oil should go about 7,500 miles or more. That means two quarts oil between changes. They claim with General Motors that is acceptable. I have never owned a new vehicle where I had to add oil before and due oil change. The same vehicle has so much wind noise coming in around the doors or windows it is hard to hear the radio. My complaint to the dealer their answer was " there isn?T a bulletin on this. That means they don?T know what to do, or won?T. and didn"T do a thing.

- Mansfield, OH, USA

The dashboard cracked for no reason in two places. One crack involves the passenger side airbag cover and the cover is coming off due to the crack. I told the dealership and they said they had seen this before but would not cover it. The crack is getting worse and the airbag cover is lifting up which will compromise the airbag deployment. There are many other complaints online of the same issue of cracking of the dashboard and all are saying the dealership will do nothing to fix this defect. This vehicle has already had to have the engine replaced twice due to defects, 3 times if you count the initial rebuilding of the engine.

- Snellville, GA, USA

I own a 2011 Chevrolet Avalanche ltz and at times when the truck down shifts it will lunge forward. I really need to have my foot firmly pressed on the brake to keep the truck from possibly hitting something or someone in front of me. It does not do it all the time and it's rather random. I feel that is worse then it happening all the time because I don't know when to expect it. I have not received any notification of a recall, but I feel a fix is definitely in order. Something is not right and it could result in a crash.

- North Providence, RI, USA

I have began to notice when slowing down (foot off the gas and coasting with foot on brake, or brake applied) at any area where my speed decreases to less than 15 mph that my Avalanche will seem to sort of lunge forward. The first time I experienced this I believed it was related to me and ignored it. The next couple of times I experienced this I thought there may be something wrong with the gas or engine. I have spoken with several other owners (who own the same year model Avalanche and Suburban - the Suburban and Avalanche are made from the same frame/body/parts) and they state experiencing the same issue. I must be cautious to ride my brakes and be read to heavily apply them now when taking an off/on ramp and vehicles are in front of me as my vehicle has lunged forward before with vehicles in front of me. I noticed here that (at the time of this submission) that two other users have reported the same incident. I am hoping that my report here will help open an investigation with Chevrolet on this issue.

- Benton, AR, USA