What is "AUTO" mode really, vs. the 2WD and 4x4???

The Gas and Diesel Engines - VQ40De, VK56DE, YD25DDTi, V9X, Transmission, Transfer Case, Oil, Differentials, Axles, Exhaust...

Moderator: volvite

What do you leave your transfer case set to every day?

2WD always
109
75%
AUTO always
25
17%
4H always, I'm hard core.
1
1%
I wish I had a choice :-(
10
7%
 
Total votes: 145

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NmexMAX
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Postby NmexMAX » Wed Dec 12, 2012 8:48 pm

That's the VDC. Traction control really. When that button is pressed, if it's off it will emit a light on your dash "VDC Off".


Calicajun
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Postby Calicajun » Wed Dec 12, 2012 10:44 pm

NmexMAX wrote:That's the VDC. Traction control really. When that button is pressed, if it's off it will emit a light on your dash "VDC Off".
Knew it had something to do with traction, not sure how it helps. Does it take power from the engine or use extra gas when turned on?

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volvite
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Postby volvite » Fri Dec 14, 2012 6:44 pm

The VDC will cut power and apply brakes when slipping is detected.

Calicajun
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Postby Calicajun » Mon Dec 24, 2012 1:36 pm

volvite wrote:The VDC will cut power and apply brakes when slipping is detected.
Interesting, had no idea that the PF would or could apply brakes to help traction (very cool).

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doctahjones
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Postby doctahjones » Tue Dec 25, 2012 10:54 am

volvite wrote:The VDC will cut power and apply brakes when slipping is detected.

i'm not saying it -doesn't-, but i've never felt it apply the brakes when spinning in 2wd. all i feel is the cut in power.

now in auto or 4wd yeah i feel/hear the abs kicking in if say i floor it in a snowy parking lot....

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disallow
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Postby disallow » Tue Dec 25, 2012 11:32 am

Per the owners manual. I decided to copy it all, as it seems to answer a bunch of FAQs:

1. How does VDC work?
2. What is the grinding noise that happens when I start driving every time I start the car?
3. My VDC/SLIP lights won't go out, what do I do?
4. When I turn VDC off, is it all the way off? (NO)

Page 5-30
VEHICLE DYNAMIC CONTROL (VDC) SYSTEM (if so equipped)

When accelerating or driving on slippery surfaces, the tires may spin or slide. With the Vehicle Dynamic Control (VDC) system, sensors detect
these movements and control the braking and engine output to help improve vehicle stability.

- When the vehicle dynamic control (VDC) system is operating, the SLIP indicator in the instrument panel blinks.
- If the 4WD transfer case is shifted into 4LO the indicator light will come on and the VDC system will be turned off. See “Transfer case shifting procedures” earlier in this section.
- If the SLIP indicator blinks, the road conditions are slippery. Be sure to adjust your speed and driving to these conditions. See “Slip indicator light”, and “Vehicle dynamic control (VDC) off indicator light” in the “Instruments
and controls” section.

If the battery is removed or discharged, the traction control system may be disabled and the SLIP and indicator lights will not turn off after 2 seconds when the ignition switch is turned to the ON position. Perform the following procedure to reset the system:

- Start the engine and set the steering wheel in the straight forward position.
- Drive the vehicle at speeds above 10 mph (15 km/h) for at least 10 minutes.
- The VDC OFF indicator light should go off indicating the traction control system is operational.
- If you interrupt the reset procedure by turning the ignition off, you will need to restart the reset procedure.

If after driving the vehicle for more than 10 minutes and the SLIP and lights remain illuminated in the instrument panel, have the vehicle
dynamic control system checked by a NISSAN dealer.

If the vehicle is operated with the vehicle dynamic control system off using the VDC OFF switch, most VDC functions will be turned off. The VDC
system will still try to transfer power from a slipping drive wheel to one with more traction when the VDC system switch is OFF. The Slip indicator
will flash if wheel spin is detected. The ABS will still operate with the VDC system off.

When the VDC system is operating, you may feel a pulsation in the brake pedal and hear a noise or vibration from under the hood. This is normal and indicates that the VDC system is working properly.

The computer has a built in diagnostic feature that tests the system each time you start the engine and move the vehicle forward or in reverse at a slow speed. When the self-test occurs, you may hear a clunk noise and/or feel a pulsation in the brake pedal. This is normal and is not an
indication of a malfunction.

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Sayantsi
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Re: 1/4 mile run

Postby Sayantsi » Sun Dec 30, 2012 1:37 pm

forgottenzone wrote:What mode then do guys use or would be better for 1/4 mile runs.
4x4 Hi, or Auto mode?
I'd assume Auto will give the closest AWD behavior, dialing down fwd power after launch, whereas 4x4 will keep power going to all wheels the whole 1/4 mile. In a straight line acceleration run, I don't think it would matter.

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SimulatedZero
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Postby SimulatedZero » Thu Jan 17, 2013 2:14 am

So, the transfer case is clutched for 4hi which allows me to shift from 2wd into 4wd without having to shift into neutral or stop?

I just want to double check before I start tearing up my transfer case. One of my friends had a Jeep Cherokee for a while and he swore that it was also a 4wd on the fly shifting mechanism. He kept tearing up his transfer case and could never figure out why...

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disallow
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Postby disallow » Thu Jan 17, 2013 5:28 am

SimulatedZero wrote:So, the transfer case is clutched for 4hi which allows me to shift from 2wd into 4wd without having to shift into neutral or stop?

I just want to double check before I start tearing up my transfer case. One of my friends had a Jeep Cherokee for a while and he swore that it was also a 4wd on the fly shifting mechanism. He kept tearing up his transfer case and could never figure out why...
Yes but keep it under 80kph or 50mph when changing. It probably causes less wear when at a stop though.

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SimulatedZero
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Postby SimulatedZero » Sun Jan 20, 2013 5:17 pm

So, I have to switch into neutral in order to engage 4Hi. I tried it without being in neutral and the transfer case wouldn't engage. It would just sit there and blink at me until I shifted into neutral. I have the three mode transfer case that has 2wd, 4Hi, and 4Lo.

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disallow
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Postby disallow » Sun Jan 20, 2013 6:50 pm

I'd be checking my tranfer case fluid if I were you. That is not normal.

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SimulatedZero
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Postby SimulatedZero » Sun Jan 20, 2013 8:24 pm

Hm, how would I go about checking said fluid?

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ShipFixer
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Postby ShipFixer » Sun Jan 20, 2013 8:31 pm

Wheels straight while you're trying to shift? Sometimes the transfer case is finicky if the front wheels are turned either way. Moreso shifting back to 2WD, but doesn't hurt to ask...

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SimulatedZero
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Postby SimulatedZero » Mon Jan 21, 2013 7:19 am

To be honest, I don't really remember. I remember trying it out on somewhat level ground and then actually having to use it when I had one wheel in air father down the trail. I will try again with wheels straight and see what happens.

Edit: So I just went out and tried it again. This time it worked. I guess I was at just the wrong tire angle or something for it to work before. It was a little finicky getting back into 2wd like you said it would be, but other than that it worked fine. Thanks for the tip.

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Zen_master
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Postby Zen_master » Mon Apr 15, 2013 6:38 pm

Thanks for the info, RacerZX.

I am currently running 2WD in my '11 LE V8. If there is steady rain I sometimes choose to use the AUTO mode (effectively AWD). But for dry pavement I prefer 2WD for maximum fuel economy. I recall reading in the owner's manual that engaging the front diff would be expected to zap some fraction of MPGs. And even in AUTO mode I can feel and hear the front diff is engaged however slightly power is being directed there.

I also own a Jeep XJ Limited with a 4.0L and the top of the line xfer case offered in the old XJ. It had similar options as the Pathfinder - 2WD, 4WD Full Time (meaning you could use it full time similar to AWD), Part Time 4WD Hi which locked the axles (meaning you should use it part time), and Part Time 4WD Lo which increased the ratio in addition to locking the axles. Just like the Pathfinder I can hear and feel the front diff in the steering wheel when in Full Time as well as Part Time.

The only difference with the Jeep is per the owner's manual it says fuel economy is unaffected by the mode you select whether it be 2WD of 4WD. Can anyone comment if they've noticed any difference in fuel economy from extended periods of using AUTO vs 2WD or perhaps 2WD vs 4WD?


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