2004 Duramax Questions?

[Buffalo]

Hi. I have a friend that is thinking about buying his first diesel, an '04 Duramax. This past weekend, he drove his brother's '03 Duramax up into the mountains, here in Arizona, and loved the power and great mileage ( ave. 23+ mpg. ). The '03 has a Duramaximizer and a Duramaximizer Tech IV, along with a K&N filter system. He just phoned me ,this evening, to tell me that he had just talked with a guy that just bought an '04 Duramax (4-10-04), and he is only getting an average of 15. 8 mpg. Basically, he's concerned that maybe these new Duramaxes aren't getting as good fuel mileage as the older ones. He would like to monitor this website for any information you guy's might like to share. So, without flaming him too badly, if you have any thoughts, suggestions or advice, he would appreciate hereing from you. Thank You, in advance, for your help. Joe.

 

[snowracer69]

I'll give him a ride in my pickup if he comes back up this way, then let him decide which he wants!



OTOH, that new Dmax has a variable turbo, or VGT. Should make for nice spool-up. Doubt you could go wrong w/ a new Cummins or Dmax, for the first 100,000 at least. Just say no to the Blue Oval though... if you make the first 1000, you might of got off with a good one!



Josh

 

[mfunderburgh]

you can get one of the first '04's with the LB7 motor if you can still find one on the lot. This is the same motor as would have been in that '03. They have now switched to what they call the LLY motor and made some changes. Check out thedieselpage.com to find out more details. Its a free site. Some of the changes with the LLY motor is a variable vane turbo and the routing of the injector lines outside the valve covers and some more horsepower. The LB7 motors they had problems when their injectors failed they were blowing out seals in the fuel lines and dumping the fuel in the crankcases. The allison has also had some mods done to it to for the 04's. One which doesn't allow all the power of the motor to come on until you get into second gear. I'm sure some of the people like Quad will find a way around that with time. I think the problem with the 04's and fuel milage lay in the fact that they have a EGR system now. :{ I hear complaints of the 600's with fuel milage problems too. Personaly my next truck is going to be a dmax because of the easyiness of making power without replacing the junk auto's chrysler makes and only having to put a good box on to make good horsepower. No replacing headgaskets and turbos to make lots of power. Just my 2cents. Matt

 

[DPelletier]

Yeah, I have advice,

Tell him to buy a Dodge.

 

[boonsur]

How was he checking mileage? If he is just looking at overheads, it'll be quite a bit off, due to the power enhancements (the computer really doesn't think it's using as much fuel as it is. IMHO, there isn't a clear economy leader anymore among the three. I bought my Cummins for other reasons:



Much bigger components, allowed by the I-6 design. Much more bearing surface area, beefier block. It's going to take a whole lot more to fatigue this engine.



Longer stroke than bore - this thing's designed to tow.



Cast iron heads. I'm still not convinced the aluminum will make it for the long-haul (head gaskets?).



Reliability - The Cummins has got a pretty good track record.



TDR!!! - If there's a problem, we can usually find a solution.

 

[DPelletier]

Matt,

buy what you like but; DC's "junk auto" 48RE has almost half the failure rate of GM's Allison AND read Georgia Cracker's post in the 3rd gen forum. He's dynoed his 305/555 with a TST Powermax CR on an otherwise stock truck (except AFE) and shows a 195. 5hp and 332. 9 ft lb increase. No replacing head gaskets or turbos necessary.



Dave

 

[mfunderburgh]

Originally posted by DPelletier

Matt,

buy what you like but; DC's "junk auto" 48RE has almost half the failure rate of GM's Allison.



Dave

Where can i get these statistics at. I am very interested in seeing who is doing these studies. I just know of someone who dynoed at 383 and had to go through the 48RE transmission already. Matt

 

[GatorRam]

That sounds normal. My Dad has an '04 with a Juice/ Attitude combo and now he's stacking it with a predator. His mileage stays at about 18-18. 5 MPG with normal driving. Of course it gets worse to more you play.



Adam

 

[DPelletier]

Matt,

Do a search. It was posted by TDR Member RBayls who works at DC's transmission plant. They had an independant company track failures per thousand units on all three brands. Results were Ford 3. 2, DC 3. 4, GM 6. ?



Dave

 

[MABurns]

18-19 MPG was best I ever got with a D/A in 50,000 miles.



23..... Like previously pointed out, I think that truck was getting "fooled".

 

[Rebel_Horseman]

My cousin just bought a new LLY Dmax with the ZF. Don't know about fuel economy though. I still have a few friends from the Diesel Page that I communicate with. The turbo is a variable unit in which the output housing size changes unlike the vanes in the Ford. My cousin says the truck will move out nicely especially when compared to his '01. Mackin may be able to add some info from The Diesel Page.



I had an '01 also and had the fuel system issues. I'd be in a bind if I had to decide today which one to buy. The Cummins is a proven motor whereas the Dmax is not as proven IMO.



Reb [><]

 

[PLaFrombois]

Try dieselplace.com search in 2500HD & 3500 trucks for HIGH MILES ???



They have a couple of guys over 500,000 miles.

 

[Big_Daddy_T]

Like the red berry said. The duramax is an ok engine. Some fuel system issues. Other than that it is pretty solid. Glad to see they moved the injectors. Thats a real improvement.



The transmission thing blew me away. I wish we could get that on paper. Id keep it in my wallet for every guy that popped off with another bad remark about the dodge transmission. Ive had pretty good luck with mine. Although a family friend is on his fourth. Ive seen worse from other makes but four does not impress me. I told that guy how to keep from losing another one after the first one and he chose to ignore me. He made his own bed.



Personally I woulnt touch the Dmax with a ten foot pole. Remember the old commercial Wheres the beef? Wheres the stroke? Its bore is bigger than its stroke. I do not think this wise for a tow vehicle. Make it quick at the strip but lacking in the hills. Chevy designed that deisel for *****s. I think they sold us diesel enthusiasts out to make it seem more potent. At least the PSD has a real diesel stroke. Undersquare for me thank you.



My neighbor gets 19 consistently. Semi rural with city driving with his dmax. I think Id take the 8. 1 for towing before the Dmax. The 8. 1 is undersquare.



Did you know the ford 300(One of my all time favorite engines)has almost a square bore and stroke. Its close. 4 in bore and 3. 98 in stroke.

 

[MCummings]

Might want to search for TDR, and former D-Max owner,, "Hoot"



Merrick