Click over to the dieselplace in the Allison transmission section,

http://www.dieselplace.com/forum/forumdisplay.php?f=41

You may want to rethink the chip option, a stock Ally cant handle much more power.  And increased mpg claims are usually just that.......claims.  Like I mentioned, poke around at the dieselplace.com.  You wont even find many "claims" about increased mpg on the Dmax.

From what Ive read;

The factory intake setup is very good to start with.  The exhaust could be changed to a larger size, that can lower the EGT, but you could lose some low end power.  Neither mod generally helps with mpg.

But dont just take my word for it, surf around.

The modules will increase the fuel flow. If the additional exhaust gases are trapped within the exhaust system, it can increase the turbo and cylinder head temperatures. This can potentially damage the motor. Adding only a larger intake system, will add to the problem. If you were only to only add  one modification to improve the performance of your truck, it would be to increase the flow of the exhaust system.

The weaknesses of many transmissions seem to be in the torque converters. If an inexpensive "shift kit" is installed, it will reduce the wear on the converter and add to the transmission's longevity. Many modules automatically change the shifting characteristics of the transmission, and correct some of the manufacturers' towing deficiencies.

If you will notice in our numerous, previous threads about the modules and diesel modifications, no one in our forum that has had them installed, mentioned having any transmission troubles. If the owners of modified vehicles continue to drive moderately, they will not experience the gloom and doom failures, the experts continue to show as facts. The real experts, are the owners who use their vehicles on a daily basis for many years, with no problems. Those are the FACTS.

Gard

Tow the same trailer with a gas engine and lets talk mileage!

When you have an 8000lb truck with 4:10 or higher rear end, that can easily pull a 16,000lb trailer.  What kind of mileage do you expect?

My nephew who works for me has gone through 5 GMC-Chevy trucks in the last 4 years.  He buys them cheap from people who have thousands of dollars into add on and then get in a bind.  He keeps them for 6 months and sells them for a profit. (at least he claims he makes money) I believe every one of the trucks he has bought has come with the Edge chips in them .  Being a 24  year old young man he has not been very gentle on the trucks.  They all have BIG tires, are lifted. It always pisses me off when he unhooks my trailers they are all to high for my hitch on my F350. At any rate, he tows  my dump trailer, my skid loader, my mini excavator every day with these trucks. And they seem to have held up to his abuse.  Based on how many of his trucks have come with the Edge I assume it's a popular chip with the duramax crowd.

On my 2006 F350. I do have the Edge Evolution and it's set in the economy mode. It adds 10 hp maybe 15hp in that mode.  I get about the same mileage around town. I get 1 mpg more on the hiway. So it's not a big improvement.  I bought it mostly so I would have the extra gauges that it offers more so than any mileage claim. I have never turned it up to the highest setting, I don't want to pay the piper for fomething breaking.

I hear ya about the mpg.  First it was the horsepower wars, now its this emissions crap.  My 05 Dmax gets the same mpg, city-highway-towing, that the Trailblazer did........go figure.

Back when fuel was so high and the difference between gas/diesel was extreme there were a few times our friend with the 6.0 gas Chevy paid LESS in fuel to get where we were going than we did.

These new diesels have plenty of power, I believe your 08 has 50+ hp on mine.  If I need more power, I would need a bigger truck to go with it.

HTB, the original posting was for an 05. Would a module and exhaust improve that D Max? Isn't that a different series motor than the 08?

Just wondering

gard, 

Your right, the original post was for the 05 DMAX.  Yes the 05 is a different series and you can safely add upgrades that WILL and DO work to improve power as well as fuel economy!  The later DMAX, 6.4 Strokers and 6.7 Cummins all have the junk DPF on the exhaust and I have had no luck doing anything with these that is low cost.

As with ANY turbo charged diesel engine, larger free flowing exhaust system and more cool air intake is the cheapest power and mileage increase you can do.

As with any other older diesels you can add some type of module to get more out of it.  My opinion I like the modules better because they not only increase fuel but they adjust air or map sensor and timming all 3, some chips only increase fuel which is not what you need for towing. 

Some will disagree with what I have posted, but "been there done that" I know what I have used and what works for me.

HTB-Kelley 

(quote HTB).... I priced the BANKS for my Dodge, exhaust, work/mpg module, intake kit and PDA without labor was around $1800.00!

Take a bunch of miles to get that paid back!!

One of your problems is that the EPA is now taking an interest in Diesel trucks...ask Kennedy Diesel about trying to defeat EGR equipment.

A second problem is chipping the Dmax above 95hp increase and the marriage of Dmax and Allison BREAKS DOWN!!!

A third problem is the Dmax computer's data history is getting MORE sophisticated and provides information to GM if the Dmax has been chipped

Now people will tell you that it will NOT void your warranty...BUT...and it is a VERY LARGE BUT...if GM determines that the Dmax failure is related to being chipped THEY WILL DENY YOUR WARRANTY...read this thread...

http://www.duramaxforum.com/forum/04-5-05-lly-duramax-powertrain/6080-blown-engine.html

AQHA - I can't remember for sure if the Hypertech allowed you to change tire size on the computer. I think it did though. And the Bully Dog did too.

Edited to add;

None of the chips help my mileage loaded. Period. No claims of that whatsoever. However, running empty, yes they did. Run the highway....fill up and check the mileage, 1.5 to 2 better. All three trucks, 8 to 12 loaded. Depended more on my driving than size of load. 

You will only lose "LOW END POWER" on natural aspirated engines!  Read up on turbo charged diesels and you will find that larger free flowing exhaust HELPS all around.  Natural aspirated or non-turbo engine needs some back presure.

Did you miss the "from what Ive read" part?

I was just passing along observations I have read from people using said products.......and pointed to where Ive read that info.  Take it for what its worth.  But I have no doubt all the aftermarket stuff is great.....thats why the factory doesnt use it.....they want you to have a subpar/unreliable product.

Some people read about things and without personal knowledge, form conclusions about what is best for others to follow.

Some people have actual information gleaned from hands on personal experiences, and are willing to relate what the results of their efforts have been.

Both express their opinions. I choose to give far greater credence to the latter.

Gard

You guys crack me up. 

So I guess I dont understand.  Ive posted my opinion gathered from the web and people I know who use these products.  I pointed the OP to the site where there are thousands of guys running these parts and can answer any question.  And you keep coming back with your (one person) hands on experiences.

What exactly do you want?  Are you trying to change my mind?  Do you feel your experiences will not be verified if the OP does their own research?  Do you just want to argue?  Thank you, but Im not interested in your experiences.  Are we done now?

Well that is totally up to you.  If we are, then we can get back to the original post!  I did not see anything on here about people wanting to argue.  It seams like you are the one who likes to strike up the arguements on this forum.  If you step back and look, it does not matter what a couple of people post you ALWAYS have something to bash or bad to say about them or their ideas.

No, I am not trying to change your mind....  The last deal I just pointed out facts about the larger exhaust on turbo diesel engines, you stated that running larger exhaust could hurt the "low end power" and I stated that it will NOT hurt it at all it only helps these engines, but it will affect the non turbo engines.! 

It takes two to "argue", if the other person can in any way back up there opinion,  then it is a discussion.  If you step back and look, technically the other person disagrees with me too......so what?  The difference is I dont whine and cry about being "bashed", if they disagree with me I either back my point with facts or ignore them.  Amazing.

Lets pretend someone said water is not wet, wouldnt you be likely to mention that is not correct?  People come here to learn. Now lets say someone is of the "opinion" that 1/2 ton trucks are not built to handle gooseneck hitches.  This is also clearly BS as the manufacturer gives tow ratings for GN hitches, so I mention that is nonsense.  How about claiming BP are dangerous?  Suv's cant safely tow a trailer?  See a pattern?  If you want to call that bashing, or something bad to say about them or their ideas, go ahead.  I guess some people are just more sensitive than others. 

Im more than familiar with engines, been turning wrenches since I was a kid.  I will type this one more time, slowly, so maybe youll understand;  The comment "I stated" about the exhaust was WHAT I READ.  I never stated I agree with it.  There are some strange claims on the web and other people may experience this same "feeling", just like some people "feel" they get better mpg.  It was worth mentioning.  If you dont agree, go find the guy who actually said it and talk with him.......I dont have a dog in that fight.