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Chevrolet Avalanche Problems & Solutions



  • MrShift@EdmundsMrShift@Edmunds Posts: 43,633
    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.
  • 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.
  • MrShift@EdmundsMrShift@Edmunds Posts: 43,633
    Well I hope that anyone who wants to go 100 mph will do it only on a speedway and not on public roads.
  • 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@EdmundsKaren@Edmunds Posts: 5,028
    A national newspaper is looking to interview consumers who have decided to hold on to their current pickup truck, rather than purchasing a new one. Please send an e-mail to no later than Wednesday, August 9, 2006 by 2:30 PM PT/5:30 PM ET containing your daytime contact information and what pickup truck you currently own.

    Karen-Edmunds Community Manager

This discussion has been closed.