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Chevrolet Avalanche Problems & Solutions



  • Mr_ShiftrightMr_Shiftright Sonoma, CaliforniaPosts: 58,461
    thanks for that info...interesting...

    I still find it hard to believe that engineers wouldn't leap at the chance to increase MPG by a simple software update. Engineers are DESPERATE for any increase in MPG, so I wonder why they would decline to do this. Makes no sense unless the increase in MPG has some negative effect on something else (like emissions, or engine longevity, etc.).

    No one has ever been able to explain this.

    Also I'm not always sold on dyno results as there are so many easy ways to cheat a dyno if you are a devious vendor.

    You might all find this interesting. Sorry if it's a bit off topic for some of you.

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  • jerrywimerjerrywimer Posts: 588
    It was a way to save the money that engineering completely new transmissions would have cost (and are costing now). But there is only so far you can push a design before things start breaking, and that means warranty repairs. How better to overcome both obstacles than by using the tricks I mentioned above. Some of those PCM changes can also result in higher MPG but don't pass emissions regulations (search for "lean burn" elsewhere to see what I'm talking about).

    Interesting tricks with the dyno, btw. :P

    There's much more to the story than just increased power output. But I'll try to let things get back on topic here, and just repeat my recommendations to search other truck forums for actual owner experiences. Some have more than just dyno logs (monitoring timing, to demonstrate how hp / torque are chopped by the PCM in some situations, is another example). :)

    Edit: Almost forgot- despite the possible gains (likely 1 - 2 mpg), I haven't done this with my 2004 Silverado. Mostly because I fear that I'd be one of those that can't resist the feeling of extra power and would trash my transmission in a short period of time. I'm fairly certain that doing so voids the warranty. ;)
  • rk2003rk2003 Posts: 1
    Have you or anyone you know had any further problems with the rear window plastic molding cracking? Mine has cracked two times since I got it in 02.
  • txyank1txyank1 Posts: 1,010
    Nope, only the early ones.
  • Hello to everything, I don't know if you have experience this problem when you got your new truck.... I barely got my truck like 3 weeks ago, my milage is arond 700 miles.. The problem that I'm having it happens just when the truck takes feels like the truck is lagging.
    Have this happened to anybody? How can i corrected? Plese advise !!! Thank you
  • melhmelh Posts: 3
    Just took delivery of my 2007 Avalanche. Thought for sure from the friends that I have that have these that the MPG would be better than my 2001 Silverado. WOW was I surprised to see that my first half a tank only got me 11.5 MPG. That isn't good at all. Any suggestions would be welcomed.
  • txyank1txyank1 Posts: 1,010
    First off be patient. You don't say if it's 2wd or 4wd. You also don't say if that's calculated or from the DIC. While it's pretty low, it will get better and it isn't terrible if it's 4wd and brand new. The DIC readings have been known to off. Although mine usually reads high (always takes more gas that it says I've used). Congrats on the new Av....I love the looks of the '07s.
  • melhmelh Posts: 3
    OK I didn't mention all the facts. It is 2WD. The dealer filled the tank up as a gift for it taking 12 weeks to get. And talking to the dealer they said that it may take up to 2500 miles before it settles down and gets better MPG. I did put on a Flo Master and was thinking about the air filter thing I have heard about. All is suppose to get better mileage, or is it just a scam. I do like the sound of the Flo Master, and I know that it doesn't mess things up, but not sure about the filter.

    I too love the looks and the features of the truck. Every year Chevy improves their thoughts. Sunburst Orange is getting many looks. Now I better get a good alarm system before I lose it.
  • txyank1txyank1 Posts: 1,010
    I too love the sound of a Flowmaster. My current '05 is the 1st truck in a long time that I didn't put one on immediately.
    I never plan on getting MPG improvement from it though and if I ever had I hardly noticed it. Same for intake, however you can get a better throttle response with an intake (mainly from an aftermarket tube , not so miuch the filter. FWIW, I just returned from a trek to NY and back. 3600 miles and averaged 21.04. Had a high of 22.1 for two separate fillups. Not bad for a near-3-ton "brick". BTW, We were weren't wasting any time. ;)
  • ralphfralphf Posts: 3
    I own an '04 2WD with a single outlet Flow Master, and a drop in K&N. I drive 100 miles a day every other week to work and back. I checked my mileage 3 weeks ago and was getting 18.2 mpg. My commute is a mix of highway speeds (65 - 80), heavy stop & go traffic, and 30-45 mph driving.

    I was thinking of adding a Tornado, but I don't know anyone who has one to see if there is a difference in their mpg.
  • melhmelh Posts: 3
    Well just got my 3rd tank of gas. Was I surprised to see the the mileage has improved. I am not for around town, up to 14.7MPG. I am still thinking about the K&N air filter, plus the computer chip when they have it for the 2007's. I am more than happy with the 2007 model. More people stair at it with envy, but not as much as the way I feel when I turn the key and drive it. Chevy tells me that the engine will take 2500 miles to break in, so I will just wait it all out. Hope you that have purchased one are as happy as I am.
  • geocingeocin Posts: 1
    I have a 2005 Z71 and when I get to at least 60 mph on the highway in 2wd, a diesling noise starts under the front of the truck.

    I took the truck in and there seems to be a service bulleting on the front transfercase because the linkage is loose in 2wd. Anyone have any Ideas how to fix, the dealers are worthless. The service manager just told me to live with it.
  • ralphfralphf Posts: 3
    If that's what the service manager told you, then demand to talk to the owner. If you get no satisfaction call your regional factory rep and explain the problems you've had with the dealer. The NHTSA has a list of all TSBs from all manufacturers on record. Check their web site.
  • Can anyone tell me if there is an aftermaket programer or "super chip that will bypass this stupid governor control on my AVZ71. Just not happy going slow.
  • txyank1txyank1 Posts: 1,010
    Yes. Diablo Predator is one that will raise speed limiter to 128. Not sure how many of the others have that capability. Personally I have no desire to drive my Avalanche even to the 98 mph limit. Although I did get real close to that once....on Texas Motor Speedway.
  • Mr_ShiftrightMr_Shiftright Sonoma, CaliforniaPosts: 58,461
    Well I hope that anyone who wants to go 100 mph will do it only on a speedway and not on public roads.

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  • I own a 2004 (bought new) and just now at 35,000 miles having some of the same problems you mentioned. Do you still own yours and if so, how did you fix the problems with "just quiting" on you. It did that to me on the interstate going 70. Did you drop the tank ?
  • elliswellisw Posts: 1
    Dear Crutches:

    I also have the same problem. I had an 05 Avalanche and every time I made a turn into a dip the front wheel depending on which wheel went first made a popping noise. I also took it to the dealer 5 times like yourself. They also replaced many items including the steering pump which then made the steering wheel make a hooting noise when turning hard turns. Now the best yet. I got rid of the 05 Z66 and bought an 06 Z66 LT. And guess whay... It does the same thing. I've called GM to no avail. Did you get yours fixed? if so, what did they do?
  • txyank1txyank1 Posts: 1,010
    The "popping" is usually the cross-member problem. Then there's the "marbles in the steering column", which is what I think the sensation is with the intermediate steering shaft problem. I had both fixed on my '03. Had an '05 that also had the cross-member problem, but didn't keep it long enough to get fixed.(bought used and had for 5 months). The '06 I have now has neither of these problems (yet), but it does have the body creaking (when starting and stopping) problem. I understand there is a TSB for this - body mounts.
  • Karen_SKaren_S Posts: 5,095
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  • I got my front windows done for $60 total and it makes it very difficult to see out of the rear view mirrors at night. I know you guys are talking about the rear windows but my after markets are performing good in the Ga. sun.
  • I have an 05 AV Z71 I bought w/ 8K mis. on it in Nov. of 05. It has had a pop in it since two weeks after I bought it. It sounds like everyone else is living with it, but I drive 50K per year and it's annoying after spending 6-8 hours in it a day. I took it back to the dealer and had the internediate steering column non-fix thing done and now I am approaching my 36K mile out of warranty deadline. The tech. @ the dealrship told me that it wasn't anything serious but things that are made right don't just pop. Something is not fitted together right.
    Is this what $40K gets you these days?
  • timf343timf343 Posts: 1
    Happy with my new 2007 Avalanche LTZ 4x2 so far, but not without a few problems... 1700 miles so far.

    Keyless entry stopped working. Changed batteries and "relearned" the fob, the car even beeps recognizing the new unit, but none of the functions work. Tried a second remote, same results.

    Brake pads are already squealing. I do not drive rough. In fact, quite the opposite. So I was surprised that the squealing I heard at the light last week was my own. Thought it might have just been wet, but it's been doing it now for a week. I shouldn't need new pads yet with this few miles.

    Anyone seeing similar problems? I'll take it into the dealership later this week, but it's a real disappointment to have to do it so soon.
  • txyank1txyank1 Posts: 1,010
    I had both the crossmemebr and intermediate steering shaft fixed on my '03. The '05 had a slight creaking that I suspect may have been body mounts as it was a little different. Only had it 5 months so never took it in. Now my '06 has been at the Dealer since last Wed. evening for LOUD creaking/popping. It happens as the front lifts and back settles on acceleration and again as the body shifts on deceleration. I told them when I took it in I suspected it was the body mounts. (There is a TSB on this). At the end of Thursday they hadn't looked at it because the suspension specialist was all backed up. (they had taken care of some other minor things though) On Friday the said they wanted to keep it because they hadn't figured out yet what was causing it. Yesterday they tell me they have some body mount shims on order and they should be in today. Hmmmm, "body mount" shims. They should spend some time on an Avalanche Site. ;) BTW, I'm really enjoying the Cobalt Rental/Loaner I'm driving. But that's a whole 'nuther story. :(
  • Within a month after purchasing my new avalance, I had to take it in because the #1-4 gears in my transmission were burnt out, they repaired the problem or so I thought. I took it back within a week because it was slipping, they couldn't find anything. At the same time I told them that on my steering wheel and on the dash my stereo buttons were very hot. Couldn't find a thing. Again! Well I was going up the I-15 towards Victorville, CA and I was in stop and go traffic more stop, so when the vehicle ahead of me went and I had room to actually push on the accelerator in drive it didn't want to go so I put it in 3rd gear and it went. The next day went to the dealer they said to bring it back any day around 1 pm so the tech, the service writer and myself could go for a drive. He actually told me to come back when I know the trans will do the same thing again, How am I supposed to know when it will do it again? It happens alot but not everytime. HAS ANY ELSE HAD THIS PROBLEM?
  • Is yours a 4WD? I had some slipping problems w/ mine as well. The dealer had to change the control box on the front differential.
    My steering buttons get hot after long periods of driving especially at night. I think it is due to the lights on the buttons, but that doesn't make it any more comfortable.
  • Same on my 03 with 70,000 miles. Did the steering shaft grease thing. Didn't help. Finally stopped being lazy and started checking the front end with a pry bar (up on jack stands of course). Bad upper ball joint. Idler arm was a little loose too. Got to love that Chinese Steel. Thanks GM.
  • avieavie Posts: 1
    I own a 2002 and have the same problem with the Avalanche just quitting. I have had it in the shop twice right after it happens and the computer does not register anything wrong. Have you had a fix?
  • Yes they finally fixed it they had to reset the computer
  • No, its not a 4x4, just a bad trans. Then they had to reset the computer, replace the rear radio, and now they are trying to figure out what the vibration noise is underneath. I only have 5600 miles on it.
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