Well, there's lots of things to "know", but most of them are simple and inconsequential... you may want your DEF full when you leave the dealer, But I never run mine completely full. There's nothing wrong to keep it full, but I prefer to keep it in the middle range and refill it when it indicates its first warning.. I can dump 2.5 gallons in and I'm good for at least 5000 to 7500 miles. And oil changes are no different than any other vehicle other than that you need to use Dexos D oil.. It's readily available even at Walmart and I use an AC Delco gold filter. I push it at least 6000 miles, except for the initial change at about 3000. Blackstone tests have proven this oil can go way beyond 7500 miles, really. But I'm trying to comply with warranty. Buy DEF at Walmart. They turn it over weekly. It's always fresh and the container makes a great oil change container to take to dump the waste oil. Fuel filter change takes 15 minutes. It's right underneath the driver's door And only really needs to be done about every 25,000 miles. I've changed mine twice and it looks pretty much like new each time I've changed it. It runs fantastically, My worst mileage is 20 miles per gal. That's usually in tough city driving in cold weather. I average 27 on any given moment and have pushed 32 on the highway.
I'm very satisfied with this vehicle. It's had a few problems. They've always been fixed reasonably quickly by the dealer and none of them had to do with the engine. Mostly electrical airbag issues. I like it so well I ordered a 25 Denali ultimate LZ0. I can only hope it will be as good as the one I have now.
This engine was designed to be about the most consumer-friendly diesel out there.... it warms up very quickly and doesn't exhibit really, any quirks of a diesel as you may think of in the past. None of my friends even suspect is one till I tell them and then tell them what kind of mileage I get. They are shocked, frankly, as most cars they are driving don't even get as good of mileage as this vehicle.