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Discussion Starter #1
Well, after 600 miles and 2 weeks with the D/A, it seems a little rough to me compared to the 6.0 I traded in, especially off the line. Some people say it will loosen up or maybe it's the fuel fix in this part of the country. I wish it would smooth out though. I just checked the HP/TQ curves and the Duramax makes the 300 HP at about 3000 RPM, and less than 250 at 2000. For those of you that have had one a few months, does it smooth out at all? Or is it just that I'm used to the gas 6.0?


Merry Xmas


Harry K.
 

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Harry,


I drove an '02 GMC CC,SB with an 8.1/Alli for two years. I traded it off on an '04 with the DMAX which I've had for 3 weeeks. I agree that there is a definete difference between the gassers and DMAX. I'm not sure exactly what you mean by "a little rough", but I love mine. I think that a lot of the differece comes from the fact that the DMAX is turbocharged. Anywho yea there's a difference, but I like it. Hope you get to like yours too.



Josh
 

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Discussion Starter #3
Josh,


Thanks for the reply. I'm going to have my buddy drive it, he's a master ASE tech whose very familiar at least with the Fords.


Thanks for the response


Harry
 

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Another thing to consider besides the engine in this case is the transmission. You've gone from a 4L80e to an Allison. The Allison is a different beast, designed for towing and other heavy usage. It is a little quirky at times. It can be very smooth, but does take some time to get used to. My wife hates driving my D/A, and she says it's because of the tranny. I liked it from day one, but certainly I'm much more familar with how it feels now that I've driven the truck for a couple years.
 

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600 miles is nothing. check again after some more hours on the clock. add some secondary filtration and some edge juice and it will smoooooooth right out
Seriously, even though my 03 felt great from the get go, yours will improve unless there is something else "wrong" with it. I would suggest running an additive as well, I have had good luck with FPPF (although I hear good things about several others including Stanadyne and Primrose) drive and enjoy
 

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I am nearing 7000 miles on mine and have had it for six months. I don't drive alot. I have the diesel for towing the wifes horse around, and because I am an aging engineer who appreciates such things; Technology, effiency, power, capacity... ummm ahhh....


The motor gets smoother and smoother (and gains noticabily in efficiency and power) as it breaks in, I wouldn't make any judgements until you get past 10k miles. Also, the transmission is adaptive and will pick shift points more smartly as time goes on. I love it, smooth as silk...

I did recently start adding stanadyne performance formula and a little stanadyne lubricity formula. It works as advertised. I think it cleaned the injectors out a tad - it is a little smoother and quieter and it seems like I have my foot into less.

You may wish to choose an additive that meets GMs recommendations/criteria. Most here seem to go against this recommendation. You can find a GM TSB on fuel additives in the TSB section of this website and make your own decision.

jeff

Edited by: dmax lover
 

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What do you think of the power compared to the 6.0 gasser? I think the cylinder pressure that a diesel makes might have an effect on soothness too.
 

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Discussion Starter #9
Thanks to all who answered during the holidays here. Jeff, Josh, bluenotem ski 1 and others. I will order the stanadyne today and will check to see what happens. Power in the initial stages is not as strong as my 6.0L was (2002HD EC w/2003 engine due to piston slap).


I will take advise and wait until break-in. I'm very easy with it so far. You're right about the tranny, it is a more diffcult vehicle to drive for everyday use which is 90%. But it is comfortable as heck and my 8 year old loves the crew cab with his own reading light. That may be another issue, this is a CC with 3.73s, I had a EC with the 6.0 and 4.10s.


Time to go shopping.


Harry K.
 

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I traded my 2500 6.0L 2WD gasser on a 2500HD 4WD D/A, and I agree that the diesel power delivery took a little getting used too. Mine has smoothed out a bit after 5,000.


Unloaded performance was smoother on the 6.0, but once I hooked up the gooseneck, loaded with my old '66 model JD3020 and a disc harrow (about11,000 lbs) there was no comparison. The 6.0L gasser sounded like it was going to throw a rod with that load, while the DMAX just pulled with ease. Not to mention my fuel miliage went up at least 4 MPG both loaded and unloaded.
 

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Just add some Juice or a Quad tune and then see how "strong" that gasser was.



One of my co-workers thought his 1500HD with the 6.0 was pretty strong.....until he got a ride in my truck.
 

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The results of a race probably would have been more dramatic but I did not want to kick him too hard. At least he got a Chevy!
 

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Harry, I second what some of the others said, diesels inherently are not as smooth (or quiet) as gas motors. They call it "noise, vibration, and harshness" (NVH).

But, FWIW, the Duramax set a new NVH standard for light truck diesels. Dodge and Ford have since updated their offerings to catch up. If you had owned and driven diesels prior to your Duramax, you would be astonished at how much smoother and quieter it is. Maybe not as smooth and quiet as a modern gasser, but they closed the gap significantly.
 

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The new diesels are getting very quiet. One of of those new Mercedes/Dodge Sprinter delivery vans drove by the other day it sounded like a gasser.
 

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One other thing. I recall the first time I drove a diesel (my new Dmax), I could have swore the cylinder firing order was somehow different than a gasser.
 

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How the hell can you tell the firing order of an engine by listening to it?? That's a good one!
 

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Discussion Starter #18
Ray, the temps here reached 50 degrees today and I left the front grill cover on. Anyway, fir the first time since I got the truck (2 weeks now), the Engine temp went to 200 deg and the Allison to about 160. The truck ran much smoother than ever before. My buddy told me that diesels always run better in the heat.


Harry K.
 

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OK GUYS here is stupid question no. 1. Does my 04 2500HD C/C D/A come from the factory with the much talked about front grill cover, or is this grill cover an option?-----------------------PHIL
 

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Discussion Starter #20
Phil,


It's coded RPO is 'V10' $55 on the sticker. It includes the grill cover and bumber cover. Pretty good quality. You can get it from your dealer or one of the internet wholesale Gm sites if it didn't come on your sticker as 'V10 Winter covers'.


Harry K.
 
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