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Comments
Here is an article I came across talking about how the corvette gets the new technology and then gets passed on to the pickups. Read the bottom of the article that talks about the cold start knock and what they are doing about it in the vettes, then it will be passed down to the pickups..
http://www.c5registry.com./2k2z06/page5.htm
Bob
funny thing though it doesnt happen all the time. Maybe a few times a week. I noticed it first of the year when it was below zero. The noise never got louder when it was cold.
Bob
This guy was saying well leave it over night so we can hear where the knock is coming from and then we can order parts so we can take care of it. I asked him how they were going to fix it, if GM wasn't even sure what the fix was, and the phone went silent....sheezzz..
I guess I'll let 'em look at it, but wonder if I can make them call me before any work is done so I can authorize it first, even though it is warranty work?? I don't know if I want these guys tearing into the motor if that is where they "think" the problem is..which we all know it is..
Bob
-Eric
Funny thing is, I read on the diesel page that one person stated he was told he could either do a top soak, or run B-12 Chemtool for 5 tanks with 93 octane and that would also take care of the cold start knock. I wonder how B-12 Chemtool compares to BG-44K??
In Colorado, the highest grade we have is 91 octane, but see that as unnessecary as 87 is what the book says...So I wonder now if the new polymer(sp?) coated piston is coming out to reduce carbon build up or if it is still a possible clearance and expansion problem??
So many questions...I will let the dealer do a top soak, nothing more, if that fixes it (sounds like only for about 500-1000 miles), then I will no longer worry about the problem as nothing is really banging around inside the engine and will set my mind at ease. But having to run fuel injector cleaner or some other type of decarbon chemical every 1000 miles on a $37k truck is outrageous!!! We'll see, I'll keep you posted.
Bob
Grrr!!! Truck runs great, drives great...pi$$ on it, I'm not taking it in for them to screw it up (as you recall they didn't have a clue what was going on and were going to look at TSB's for the solution and a little guessing)... I guess this is what GM wants us to do, get so frustrated that you just ignor it and let them get away with it. Now thinking about getting rid of my extended warranty and getting rid of the truck after 3yr/36k miles and go diesel..at least if it has the knock you wouldn't be able to hear it anyway!!! That is of course if I buy another GM....
Just venting a little...I think I am done for a while..
Later,
Bob
Run premium when towing travel trailer, pulled over multiple 10,000' passes last weekend, running close to redline both up and down.
No funny knock, other than some ping on low octane gas.
I do have a heck of a clatter from the manual transfer case shift rod. Fixing tonight.
-Eric
To the gentlemen who posted that he was a Ford man until he bought his Chevy, you said you drove both and there was no comparison, but didn't elaborate on that. What caused you to decide on your Chevy?
I've driven neither, but hearing all that is going on with the Chevy line and their drivetrain and engine problems I am about convinced I don't WANT to drive one. Anyone have any experience with the GM manual transmissions, and how reliable they are over the long haul?
Also went to the site concerning excessive oil consumption and read it. How many of you with high oil consumption drive in low gears at high RPM's? Sounds like they feel they have narrowed the problem down to that. Now if you want to continue to drive that way they have some new rings they can put in your engine and fix that.
The pics I have of my truck on my picture trail account have those cheesy little Ed Bozo' #1 crap plates on, can't wait to get my updated pics of my truck with accessories to switch with...guess I could white it out with an editor though....
http://www.picturetrail.com/4x4man
Bob
With regards to your questions about the driveline issue, other than the cold start knock, my truck has been flawless in the 4 months that I have had it..have about 4,300 miles on the OD. The Allison tranny works exceptionally well, no launch shutter or vibration at all. My truck has the one piece drive shaft (Extended Cab shortbed).
I was able to test drive the furd v10 and d*&ge v10 at the GM truck show in motion show here in Colorado a couple of months ago. They also had the big three diesels towing about 7k that we could test drive also. The furd v10 was the only thing that thought about coming close to the 8.1L in acceleration with the gasers, but the d*&ge v10 didn't feel as powerful in seat of the pants. I'm not a furd or Chevy man, just buy based on need or want as the case my be. If/when something comes out better and I can afford it, I will probably buy it and keep it for a few years until the next....
My truck doesn't have an oil consumption problem (thank god!) I uses maybe a half qt in 3k miles, there really isn't enough miles on the motor yet, to really get a good judgement of that, but so far so good. The last time I checked the oil it was like a quarter of a qt low in about 1,300 miles, nothing to worry about here...
Sorry for the book, but thought I would offer my opinions on the matter. Knowledge is power, yet is also the cause of high blood pressure when you know something isn't right and there is nothing you can do about it and big brother doesn't care.
Bob
-- Don
-Eric
-- Don
Best of luck
I wouldn't worry about it too much
Hunter
Good luck
Bob
BUut when i got to chevy they said they cant do nothing until the service rep comes in. which i have an appointment with tommaro. What i would like to know is if anyone is having a problem similar to mine. i would love to have any one with the allison trans in there chevy silverado to please let me know how there trans sounds. wether its loud or not . i would love to have some feed back to take with me tommmaro when i go . my whine noise can be heard the truck is idling or on the road . thanks very much for your feed back. by the way i love the truck if chevy would just fix that whine
As for the 8.1 yes I have cold start knock for 30 to 40 seconds .it also used a quart of oil every 800 to 1k mi till it hit 10k but used only 1 quart in the 3500 after that.Now with 13,600 it still knocks and whines.
Anyway thought I would let you know. Also planing on getting a stethoscope as I want to follow up on a hunch by a friend as well as some comments by others on another board who said the noise is coming from the poppets in the fuel injectors. Some heard the exact noise using the stethoscope and listening over the fuel injectors, yet heard no noise next to the heads or block. Either way I am now not concerned about the knock or should that be the knock I DON'T have anymore!!
Bob
Anyone used syn ATF in their Allison??
Jeff
Anyway, I plugged the Dmax block heater in last several days. Put a smile on my face to get in that cooold truck and have instant heat. Diesel also comes with a front end mask to cover up the grill. Dmax needs it or you don't get enough heat. Runs better too.
Tom
Kyle
Transmission filter is next, maybe get to tow the sleds so I can change out the diff fluid.
Ruddster: Allison recommends Castrol TranSynd transmission fluid in all their transmissions. I would look into that for a replacement.
-Eric
Bob
I then read a post on another site that stated their knock went away after a hard tow. So I decided to drive down a particular stretch of road in second gear every afternoon on my way back from work about 5 miles or so for the last couple of weeks. So far so good, it was warmer this morning at 24 deg. but still no knock and sounds sooooo good!!
Bob
I changed my tranny filter a couple of weeks ago, magnet had some stuff on it, nothing to worry about. Got the filter for 8 bucks and change, dealers wanted upwards of 30 bucks!! Told that to the guy at the Allison shop and he laughed and stated a lot of the dealers buy the filters from them!! I am thinking GM is doing the same over charging thing for their grape juice among other things. Funny I can pick up an oil filter for $4.25 for my 8.1L, the only reasonable price I have yet to see!!! What is this, buy and expensive truck, buy expensive fluids and/or maintanance items??
It took about 1 qt to refill the tranny after the filter change, I prefilled the filter, put the magnet on it, spun it up there and checked the cold level of fluid, it was good so I let it warm up to full op temp. It was about 3/4 of a qt or so low. I didn't check the fluid level before the change, but thought I had checked it at some time prior to the change and the fluid was full.
I am thinking about changing to the deep pan next spring in preparation for towing my parents 5er. I figure the extra capacity coupled with changing to Castrol TranSynd will keep the tranny nice and cool and well protected. I will try double trailering for the first time next year so by that time I will buy my own digital camera to take pics of this long load, borrowing the neighbors camera is fine, but I still haven't received the pics from the dash removal yet!!!
Oh well, it outta be a white knuckle experience towing a 25 ft 5er and an 18ft boat (23 ft from front of trailer to transom) behind the 5er.
Bob
http://www.mag-hytec.com/differential%20covers.htm
I figured since I was going to remove cover to change fluids, why not add additional cooling with finned aluminum cover that holds double the amount of lube? But alas, the pocketbook has run dry... for now. Maybe in the spring.
Where did you find the TranSynd? Been to a few local parts stores, but no luck. Ended up buying trans filter from dealer for $14 as the local "Truck" stores didn't have them, and none of the parts stores could even get one. Only have 3.5K miles, so not in a hurry, but would like to have everything beforehand so not in a mad dash at the last minute.
-Eric
I thought about a new diff cover, but right now I am not towing anything that will significantly heat up the diff, so I am gonna wait and spend the money taking care of the tranny instead. Not sure why GM didn't put the deep pan on the 2500HD's in the first place....not like an extra inch or two is gonna cause clearance problems.
$14 for the tranny filter from the dealer is not bad considering what they wanted for them here.. I don't expect the local autoparts stores to have the tranny filter, heck I can't even get an AC Delco oil filter for my 8.1L from any of the parts stores yet. Finally found a Pure One oil filter, but have one AC Delco left from when I talked the dealer into a lower price for oil filters so I'll wait a little longer.
Bob
I just bought a new filter at our local Allison/Detroit Diesel dealer in Reno for $7.50. The also had TranSynd for $31/gallon, which is slightly better than the $26/qt I was quoted from Valley Chevrolet in Carson City, NV. I will change the filter @ 5,000 miles per the Allison manual & change the ATF @25,000 per my chevy manual.
Jeff
Kyle
http://www.allisontransmission.com/product/series/1000series_listings.jsp?PublicationType=Service
You can click on Operator's Manual and select the 1000 series then there is a spot where you can download it on the next screen.
Bob
I get so darned mad every time I see their commercial with the owner promising a great deal..."or my name isn't Don Jack". I saved over $1,700 by NOT buying my truck from Valley. Plus, when I called thier Service Dept., the bonehead service writer told me that my Allison was a "100,000" transmission, in that it needed no maintenance for the first 100,000 miles! I then asked how many of these he has seen or worked on, and he said none! I wouldn't recommend Valley to anyone, Sales or Service!! If you want a good deal go to Dave Smith Motors in ID. Any chevy/gmc truck for $217 over invoice!
Jeff
http://www.thedieselpage.com/cgi-bin/Ultimate.cgi
http://ford-diesel.com
Hunter
PS, I have a GM Duramax 3/4 Ext Cab 4x4 and love it!
-Eric
Right now your speedo is off by about 8% - 4.68 mph at 60 mph- you are going 64.68 mph when your speedo reads 60.
With the 3.73 setting your speedo will be off by about 2% or about 1.2 mph at 60mph - but now when your speedo says 60 you are only going 58.8 MPH.
This is because your tires are 8 % larger, the difference between 4.1 gears and 3.73 is about 10%.
I know someone who had this done, but the first dealer he talked to told him it could not be done, found another dealer that said no problem - charged him 1 hour labor - which was about $50 back then - more like $75 (?? guess) per hour today.
I have put larger tires on several trucks but never bothered with changing the speedo. I set the cruise control on the speed limit - and figured even though I was really going 3-5 MPH faster - the chance I would get pulled over was small.
August (8k miles), took it in again for knocking.
They say "engineers are working on it, bring it back in Nov. or Dec. and we'll fix it." Early Dec. I took it in and they say its normal. I say I don't like it. They have a customer service person call and offer me an extended warranty on the engine for 5 years or 50k which ever comes first. I say no thanks, I'd rather have an engine that sounds right. If I was going to keep it after 36mo/36k I'd buy an extended warranty anyway (bumper to bumper).
Anyone know how to get started on a Lemon Law buy-back?
Other than that and the mileage(12mpg at the very best) I love the truck. Would like to try the Dmax.
http://agmlemon.freeservers.com/
I see several posts regarding road speed vibrations mentioning problems in the 1600-2000 rpm range, although this might be the issue my bet is still on a engine management problem. Also the problem does not seem to be sensitive to engine speed and occurs at road speeds with the engine running 2300-2400 rpm in high 4th gear.
If anyone has had this problem and has successfully resolved it I would sure like to hear what was done. And yes the engine does clatter when first driven for the first 3 or 4 minutes but that is a separate issue.
-- Don
Only complaint is the gas mileage. Best in town is 11.5mpg, best on highway is 15.5. But towing a 7500# travel trailer at 65mph and I get a little better than 9mpg.
Jim