Last post on Oct 16, 2006 at 7:49 PM
You are in the Chevrolet Avalanche
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Chevrolet Avalanche, Auto Body, Engine, Suspension, Truck
#495 of 534 Re: Avalanche 4 wheel drive noise [kokanee]
Apr 10, 2006 (11:34 am)
I have an '02 Avalanche and have been experiencing the same thing. I also took it to the dealer and they told me it was normal. What I have found is when I engage the 4 wheel drive on a hard, dry surface, I hear the grinding noise. However, when I engage the four wheel drive in a muddy, snowy, or other slippery condition, the four wheel drive works great with little noise. I also experienced when I would turn sharp on a hard dry surface in four wheel drive, the wheels would actually bind up to the point where they would stop the vehicles progress forward. What was concluded from all this and from talking with others, the 4 wheel drive system is simply not intended to be engaged on dry hard surfaces. I think your "noise" is normal and you should be fine. I don't know if this offers much comfort, but it is what I have experienced with my Avalanche.
#496 of 534 Re: Sunroof problem [rudy331]
Apr 11, 2006 (11:57 am)
My wife has a 2002 Avi with the same problem, what did you do to remedy this problem?
#497 of 534 Re: Avalanche 4 wheel drive noise [turibe]
Apr 12, 2006 (11:19 am)
I certainly appreciate your reply. I took my truck to the dealer, and as expected...they said the noise was normal.
When I get off work tonight I'll take a ride in some sand and see how it sounds.
Once again, thanks for your reply.
#498 of 534 Engine Performance Booster
Apr 22, 2006 (9:17 am)
I am thinking of getting an engine performance booster for my avalanche. Has anybody else done this and what has been your experience with them?
#499 of 534 Re: Engine Performance Booster [turibe]
by MrShift@Edmunds HOST
Apr 22, 2006 (10:10 am)
You mean something in a can, an additive? That's just snake oil....don't bother IMHO. I've tried them all, they are illusory.
If you mean a MECHANICAL device, then it depends on what you are talking about.
#500 of 534 Re: Engine Performance Booster [Mr_Shiftright]
Apr 24, 2006 (8:06 am)
I should have been more specific with my questions. What i was referring to are the "chips" or computer softwares you can install into your vehicle to change the factory settings for air/fuel ratio, timing aspects, and a few other things in order to either get more horsepower or better fuel economy.
Most people use them for the diesel vehicles, but i've seen/heard of a few for gas engines.
#501 of 534 Re: Engine Performance Booster [turibe]
by MrShift@Edmunds HOST
Apr 24, 2006 (10:54 am)
Well all I can tell you is what I read from the "experts" and they all seem to say the same thing about chips...some work, some don't, and some work but aren't good for your truck.
So how to sort all this out? I think you need to shop carefully, first of all to determine the reputation of the chip vendor, then to ask them HOW they get the performance they claim (are they bumping the timing, or just extending the transmission shift points?) and also how much MPG you might LOSE (I'm a real skeptic about any device that claims to give you more power AND better mpg---that sounds rather contradictory to science).
Then if all this passes muster, I'd try to find someone who has already bought and TESTED the chip over time and get his/her testimonial.
My feeling is that factory engineers are very smart guys and that they don't leave lots of power on the table---and if they do leave a little HP on the table, it's a good idea to find out WHY they didn't add it to the stock vehicle. Most likely answers would be driveability in everyday use, and MPG.
#502 of 534 Re: Engine Performance Booster [Mr_Shiftright]
Apr 24, 2006 (12:13 pm)
Its possible to improve both power and economy with just a reprogrammed PCM. Search other truck forums for proof (dyno charts, etc. from end users and not just the people trying to sell you their chips).
Most people never see the actual posted hp and torque with their vehicles thanks to built in torque management. This retards engine timing with gear changes, gives soft shifts, and other similar tricks. The main reasons for this seem to be related to emissions, driver preference for "soft" shifting, and transmission life.
The 4L60E transmission in current GM trucks is long in the tooth, tracing back to the TH700R4, and wasn't originally designed to handle the power being made by the current crop of V8's. Part of the changes made to allow the bigger engines was softer shifts (reducing the amount of sudden torque load change) and engine retardation during shifts. This also reduces overall fuel efficiency and engine power output.
So, if you don't mind firmer shifts and aren't too "enthusiastic" with your driving you can benefit with a reprogram. You can also shorten your transmissions life if you enjoy yourself too much though.
BTW, GM isn't the only manufacturer doing this. Most of them have similar issues.
#503 of 534 Re: Engine Performance Booster [jerrywimer]
by MrShift@Edmunds HOST
Apr 24, 2006 (12:17 pm)
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.
#504 of 534 Re: Engine Performance Booster [Mr_Shiftright]
Apr 25, 2006 (5:05 am)
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.
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.