I read the sticky where one person mentioned they didn't really notice a difference, but I was curious what the consensus was.
I have had a 2011 LE for a few months and have had it in AUTO the entire time. According to the computer I am getting about 17 MPG overall.
Anyone think I would see a marked difference but running 2WD all the time?
AUTO vs 2WD and fuel economy
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Barjrob1972
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I don't have auto mode on my '12 Silver and only have the selectable 4wd option. In 2wd, low 19's to high 18's is about where it sits on highway but average is between 15-16. I usually keep a heavy foot on the skinny pedal as after all, holding up a 12 4E foot can get tiring, or so is the excuse I give to my wife. I was a little disappointed but since my other DD is a lifted and tuned F150 on 35's with 4.56 gears that gets about 10-12 mpg on a good day, that makes it a little easier to swallow.
When in "AUTO" mode, with the vehicle at idle, in reverse and at speeds under 35mph, an electric pump (called the "transfer motor") runs to lubricate the wet clutch in the transfer case, which wouldn't happen in "2WD" mode. This does put a very slight load on the electrical system. I think for this reason, Nissan says that "2WD" mode gives you best fuel efficiency. That said, I've had my 06 LE for almost three years, initially using "2WD" mode all the time and then switching to "AUTO" mode all the time about a year later. I haven't noticed any difference in fuel mileage between the two. I averaged 17-17.5 combined before and still do afterwards.
Re: AUTO vs 2WD and fuel economy
The only way to really answer that is for you to run for awhile in 2wd and see. Nobody can say for sure how your driving will be impacted by making that change. smj999smj makes a good point about the transfer motor, but I still think there would be some additional drag in the drive line. But i'm not that familiar with how the Nissan system works. I now with my Suburban it gets about 1 mpg better in 2wd vs auto. I think the bigger point for me is that 99% of the time there's just no need for 4x4 so why bother keep they system engaged?OtterAKL wrote: Anyone think I would see a marked difference but running 2WD all the time?
If you are in "AUTO" mode, you aren't in 4x4 mode unless there is a slip condition, or, based on inputs, it anticipates a slip. For example, if you are sitting at a stop and take off at wide open throttle, the system anticipates that you are going to spin the rear wheels so it will begin to apply power to the front wheels via the wet clutch. Otherwise, there would be no load on the front drive line. "AUTO" mode would come in handy on wet or gravel roads when one would normally not be in "regular" 4WD mode, which is not a bad idea since the R51 throttle can be a little "touchy" if one's not used to it.
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