New Duramax Owner

============== Curtis:

Congratulations on the new truck.

You should take a look at

and its forums. Non-members can look at the forums without joining, and by using search you can probably find lots of answers (or at least opinions) on all kinds of Duramax questions.

Now, as to your specific questions:

The oil change indicator on the Drivers Information Center (DIC) is supposedly based on how hard you are running your engine. In normal driving, it would lead you to believe that oil can go 10,000 miles or more between changes. And the Duramax oil stays amazingly clean for a diesel.

I would change oil and filter with conventional oil at 1500 miles, again at 5000 miles, and then go with either synthetic CH-4 or CI-4 rated oil on a 5000-6000 mile cycle, assuming you are not towing big trailers.

GM recommends 15-40 oil except in very cold weather, when 5w-40 is recommended to avoid over pressure when the engine is cold.

I have heard the factory fill is Mobil Delvac 1300. Other great conventional oils are Delo 400 and Shell Rotella T, all on the shelf at Walmart for around $6 a gallon (an oil change in a Duramax is 10 quarts).

Many, however are running synthetic oil, 5w-40 year round. The leading brands are Mobil 1 Delvac, and Shell Rotella Synthetic. The Mobil 1 Delvac is hard to find retail, but can be ordered from Mobil distributors. The Rotella Synthetic is sold by WalMart and often goes on sale for under $13 per gallon. I heard, however (not confirmed) that WalMart may be phasing out this brand. I run Rotella Synthetic.

For filters, an alternative to factory filters is Baldwin, a well respected brand. I buy mine in volume discounts from

in Boston Mass.

For fuel filters, I think it depends on where you buy fuel. If you are a gypsy and buy fuel from "questionable" places, you will need to change more often than if you always buy from large volume locations, such as FlyingJ. I think 15K is recommended. From the guys at the Dieselpage, some are adding 2 micron filters in series with the stock filter to eliminate microscopic dirt to protect their injectors.

Nobody at Dieselpage seems to be particularly worried about turbo shut down, but I think common sense is in order. As a practical matter, I don't think you are going to be running real hard and then chopping off the engine before things slow down/cool down from peak levels.

Make sure you do not forget to change the spin on filter on the Allison at 5000-7500 miles.

In winter, it takes a long time (around 10 miles) for the Duramax to fully warm up. If you are going to use it for short commutes in winter, you may want to put on the grille cover that you should have received with the truck in northern climates.

And expect to see some amazing fuel economy for a truck of that size. I have a 2003 Crew Cab and see as high as 21 mpg on long distance interstate type driving, and usually at least 17.5 in short range driving.

Best wishes,

Ray

Curtis:

The Allison filter is very easy to change. It just sticks down from the bottom. Looks like a little spin on like you would find on a small 4 cylinder engine. When you remove it, there will be a magnetic "donut" on top. Make sure you put it on top of the new filter and reinstall it, do not accidentally discard it. The only transmission oil that "comes out" when you spin off the filter is the oil in the filter itself, maybe 1/4 pint or so.

The only filter that is at all difficult to change is the fuel filter, because of limited clearances.

Hastings are also supposed to be good, but Baldwin at

has all the Duramax filters, oil, Allison, fuel and air. So I just ordered them all at once.

Have fun!!

Ray