"Real World" diesel fuel mileage on Duramax

[jeffsw6]

I have heard 500 miles and 5000 miles but never more. I personally would call your service dept.

I checked the '11 manual and it says to change the ATF filter at the first engine oil change. I agree with you, call to service dept should give the right answer.

I remember when the break-in and service schedule in GM vehicles was a nice table in the owner's manual that was easy to understand. They really need to go back to that, because the new way sucks.

 

[Reg]

Seems like fuel mileage varies on the ones around here. My 2007.5 LMM was averaging 19-20 unloaded until an updated ecm reflash then it averages a very consistant 17.5-18 unloaded. The "liar" DIC is always within a tenth or two so I gave up hand calculating.

One friend bought one at the same time and his has struggled to get over 11 mpg since day one. Another bought one after ours and his gets 18 average.

Two other guys in the area have 2011 3500 duallies w/ the DEF and seem very happy. One went from a Dodge duallie and the other had a 2007 GMC duallie.

I am planning on dropping the DPF after the warranty runs out this fall.

The dash does have some issues though on the older ones:
one million miles - Diesel Place : Chevrolet and GMC Diesel Truck Forums

Winter fuel has less energy per unit of volume, that affects fuel (dis)economy adversely.
I like to THINK that I can tell the difference when the higher energy blend is in - and what I feel usually correlates with what the DIC tells me.
Of course that is Spring time - which affects me favorably anyway, so maybe I feel more energetic and project that into the truck (-:

I still maintain that the biggest factor in all this is in HOW you drive, WHAT you drive is secondary and once you buy it you HAVE it, usually for a while.

 

[Diamondpilot]

On your D-Max, I thought if you had DEF, your truck didn't go through a regen cycle. I thought the DEF elimnated the DPF. I'm just guessing though.

All trucks from 2008 on have a regen cycle. Ford and GM use DEF fluid to increase the temp and clean the DPF filter on the 2011 and later models. The 2008 through about 2010 just dumped more fuel in to create the higher temps. This is also how the Dodges work, just dump in more fuel like the 2008 to about 2011 Ford and GM's did.

Chris

 

[Superduper]

Taking your problems out on Dodge is dumb in this case....

You sound like you had a different Dodge experience and that is fine. I am sure that my experience was not representative of all dodge owner's experiences. But I don't think I was dumb at all to have ditched Dodge. It was clear to me that on any warranty issue, I was going to be guilty until proven innocent. The truck had an issue and it was always going to be MY fault unless I proved them wrong. There are so many trucks out there, so many manufacturers -- why should I give them another chance? As an individual, the best and sometimes, only practical recourse we have when dealing with large companies who mistreat us is to walk and take our business elsewhere. If you ask me, it would be dumb to double down after an experience like that. I might be wrong but it seemed more to me like that was a company culture or policy to rake the customer over the coals on warranty issues. Maybe it was just this dealership, maybe directive or training from the regional bigwigs, or maybe even higher up. Why should I care? Life is too short -- just went elsewhere and was happy since. For me, experience is life's greatest educator and experience is what guides me. Your experience with a Dodge dealer in YOUR area might differ. For me, this was the right decision and I never doubted or regreted it. I got screwed and walking was the right thing to do. Anyhow, we are drifting off on a tangent here for which I apologize. This dodge thing was only posted in response to someone who suggested that maybe not babying the truck before driving on the freeway was the cause for it's failure. I can't get behind that suggestion -- owned many vehicles before and after and never had a problem like that.

Regarding the 500 mile auto tranny filter replacement: You guys got me worried about that. So I read through my owners manual as well as my duramax manual and found nothing about replacing the auto tranny filter in short initial inteval. In fact, in the maintenance intevals chart, it looks like 97,500 is the recommended filter replacement. So I called my dealer and asked them if I needed to take it in (it's been a week and almost at 500 miles). They said no, there is no need. GM "recommends" we service the transmission (fluid and filter) at 25k miles but otherwise, to follow the recommended intervals in the manual. Obviously, if the recommended interval was 500 miles, which comes fast, the dealer would be doing tranny filters many times/week.

On a positive note, I spoke with the service advisor who was very friendly and I was told that the allison transmission is bulletproof as they have yet to replace one single transmission. That is very good and promising report since this dealer is in a metro area and sells lots of trucks.

 

[jeffsw6]

Regarding the 500 mile auto tranny filter replacement: You guys got me worried about that. So I read through my owners manual as well as my duramax manual and found nothing about replacing the auto tranny filter in short initial inteval.

It might be that this has changed in your model year, but in the 2011 trucks, in the regular owner's manual section 11-3 it says: For vehicles with Allison Transmissionｮ only: At the first engine oil change only, replace external transmission filter.

The purpose of this is to remove break-in debris. I would double-check your manual to be sure. The dealership people are right, though, the Allison transmission is very durable. Only 3 have ever failed and they are all diamondpilot's neighbors! :laughing:

 

[timswi]

It might be that this has changed in your model year, but in the 2011 trucks, in the regular owner's manual section 11-3 it says: For vehicles with Allison Transmissionｮ only: At the first engine oil change only, replace external transmission filter.

The purpose of this is to remove break-in debris. I would double-check your manual to be sure. The dealership people are right, though, the Allison transmission is very durable. Only 3 have ever failed and they are all diamondpilot's neighbors! :laughing:

:drink::drink:

 

[Dmace]

The dealership people are right, though, the Allison transmission is very durable. Only 3 have ever failed and they are all diamondpilot's neighbors! :laughing:

Ha Ha! :laughing:

 

[Diamondpilot]

It might be that this has changed in your model year, but in the 2011 trucks, in the regular owner's manual section 11-3 it says: For vehicles with Allison Transmissionｮ only: At the first engine oil change only, replace external transmission filter.

The purpose of this is to remove break-in debris. I would double-check your manual to be sure. The dealership people are right, though, the Allison transmission is very durable. Only 3 have ever failed and they are all diamondpilot's neighbors! :laughing:

Nope, never had a issue with mine and just leaking cooling lines and a front seal on my neighbors. Good one though.

Really though, it used to be 500 miles. I guess things have gotten better as time goes on.

Chris

 

[WilliamBos]

Nope, never had a issue with mine and just leaking cooling lines and a front seal on my neighbors. Good one though.

Really though, it used to be 500 miles. I guess things have gotten better as time goes on.

Chris

For the $10 the Alli spin on costs, would not hurt to change it every oil change, would it?

Allison External Spin On Filter

 

[marcusmiller360]

I didn't read the whole thread so forgive me if I'm saying what's already said, but some states don't require emissions testing. If you live in a state like this, you might try "deleting" your diesel engine EGR and DPF on late model trucks. I did on a Dodge 3500 Mega Cab, and it saved a lot on diesel! The emissions aren't bad either, if you run 100% bio diesel (which would be a problem with the DPF, it'd break the engine, without it you are good to go):thumbsup: