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...

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

2WD always
105
76%
AUTO always
23
17%
4H always, I'm hard core.
1
1%
I wish I had a choice :-(
10
7%
 
Total votes: 139

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smj999smj
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Postby smj999smj » Tue Nov 17, 2015 9:04 am

DavidUk11 wrote:With my car, in 4wd Hi or Lo there appears to be a lot of stress on the transmission doing the right manoeuvres I have to do shifting my boat on and off my drive (Hard pavement).

I will have to have a look at the front and rear diffs and see if there is is anything that might lock them. If it is system using the brakes that is not a problem as the wheels do not slip on the tarmac. I am wondering if putting a switch in the power to the electric oil pump might free up the centre diff and make things easier. I will have a re-read of this thread which is very informative thanks.
Actually, there is an adjustment that can be made using a capable generic or Consult III scantool to help that out. The setting is normally left as is unless a customer complains about the binding that occurs during low speed, tight turns. Overall, it is considered a "normal" condition and is stated so in the transfer case section in the factory service manual (in my 2006 manual, it is on page TF-130).


DavidUk11
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Postby DavidUk11 » Tue Nov 17, 2015 9:49 am

That's very useful information I will have a look. I have found the Consult 3. Could you suggest a reasonable alternative or laptop or tablet (Android) interface please?. I am not familiar with car diagnostic electronics.

Problem is, I would ideally like to be able to lock and unlock the diff at will.

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labsy
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Postby labsy » Sun Jan 17, 2016 7:35 pm

Hey,
I didn't go through all posts here, so my apology if I missed the answer.

What bothers me is 4LO.
Patthy is AFAIK equipped with ELSD aka Electronically limited slip diff, which means that ABS/DSC systems work together to prevent the wheel with less traction to spin freely, so the torque is given to the blocked wheel.

But in 4LO this system disengages and DSC light comes on, meaning DSC is OFF.

So what does it mean:
- is in 4LO only DSC OFF, but ELSD is engaged?
- or in 4LO no DSC and no ELSD kicks in?

kevinthefro
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Postby kevinthefro » Sat May 14, 2016 11:58 am

Sorry for the late answer, but, per the owner's manual, ABLS (Active Brake Limited Slip) is always active. It does not turn off when VDC is turned off. It does not turn off in 4LO. In 2WD mode it works on two wheels, in 4WD mode it works on four wheels, or, more accurately, it works on two pairs of wheels.
It is active IF you are going above 3-6 mph. It's not for rock crawling.

http://www.manualslib.com/manual/458339 ... l?page=366

I exercise mine regularly, in 4LO, and I can hear it engaging - the RPM will rise a bit, then drop, as a wheel spins for a half second, then is braked.
Two weeks ago I climbed a particularly nasty hill of loose rock, bounced all over the place but it never stopped. My buddy followed me in his Wrangler, got stuck halfway, spun his tires then snapped both rear axle shafts. I had to go back down part way and use my car as an anchor point to winch him to the bottom.

I watched a 2WD Xterra going up a hill and I could see his tire spin, grab, spin, grab - he had no idea ABLS was doing its thing and keeping him from getting stuck. Pretty clever system.

Netdewt
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Postby Netdewt » Wed Dec 14, 2016 9:04 am

I know I am asking a question that is answered somewhere, but I have not been able to find it. I have a 2008 LE with all mode. Do any of the differentials lock in 4 hi or 4 lo? I'm having a difficult time finding specs, and I also have very limited understanding of 4wd systems.
However ultimately I think it doesn't especially matter, if you're doing some rock crawling and getting wheels in the air I bet you're in 4Lo anyway which is unequivocally always locked.
Does this mean locked... locked? Or a Nissan workaround version of a locked diff?

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smj999smj
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Postby smj999smj » Wed Dec 14, 2016 1:39 pm

The differentials don't lock in the R51 (unless you install an aftermarket locker). The R51 has electronic limited slip. Both the front and rear are open-style differentials. It uses the anti-lock brake system, when needed, to apply the brake at the free-spinning wheel, which puts the power to the wheel with the traction. It works pretty well.

Netdewt
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Postby Netdewt » Wed Dec 14, 2016 7:24 pm

Thank you for the simple explanation. :)

Snowcaps
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Location: Calgary

Postby Snowcaps » Sat Sep 02, 2017 11:18 am

Hello RaceZX,

Thanks for the detailed explanation on the operation.

"There are two hydraulic oil pumps in the transfer case which provide oil pressure forcing the wet clutch plates together as requested by the transfer control system. One is gear driven from the input shaft, the other electric to provide pressure when the vehicle is stationary and up to 34MPH. If you are set to 2WD the electric oil pump will not operate at all at any speed, which is the only and probably VERY small MPG benefit to 2WD. I'll test this some time for giggles...should be truly zero difference if driving over 34MPH"

Not sure if you can answer this question below

If I disconnect the rear drive shaft at the axle housing and flat tow 4 wheels down with the switch in the 2H position will the transfer case get damaged due to a lack of lubrication since the front axle drive shaft will be spinning in the transfer case?

Thanks

Snowcaps

2008 V8 LE Pathfinder

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smj999smj
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Postby smj999smj » Sat Sep 02, 2017 2:14 pm

The safe thing to do would be to flatbed the truck. If you had no other choice than to tow it on all four wheels, I would remove the front driveshaft as well disconnect the rear shaft from the rear diff.

Snowcaps
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Location: Calgary

Postby Snowcaps » Sat Sep 02, 2017 5:02 pm

Ok, thanks for the reply.

I was wondering if I only installed the Remco drive shaft disconnect that I would only need it on the rear drive shaft to flat tow it behind my motorhome.
http://www.remcodsc.com/driveShaft.php,
Since from what was described by RacerZX, it sounds like the input shaft operated hydraulic pump is only needed to provide oil pressure to force the wet clutch plates together or does it have a dual role and also pumps oil to other areas in the transfer case i.e. on the chain etc,,, via oil channels inside the transfer case or are those areas of the transfer case being lubricated by the splashing of oil, similar to the rear axle?

Thanks again for your input.

Best Regards,

Snowcaps

sportbikerider
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Postby sportbikerider » Mon Mar 19, 2018 2:16 pm

(edited: Nevermind. I just tested it on my snow/ice covered driveway and in both modes, I could get one rear or front wheel to spin and keep spinning)

Hey guys...great thread. I read all 6 pages and might have missed the following.

If you are in 4HI or 4LOW, does it ever lock the wheels together and over-ride traction control systems so that the same power goes to both wheels regardless of slip? Or is the traction control system going to detect slip and start braking that wheel?

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smj999smj
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Postby smj999smj » Tue Mar 20, 2018 10:07 am

They are open carrier diffs, front and rear, so, it can't lock them so that both wheels turn on a given axle. That's not a function of the transfer case but of the electronic limited slip system, which will lock the spinning wheel via the brakes on a given axle, allowing the power to go to the wheel with the traction.

m.powerpt
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Postby m.powerpt » Tue Mar 20, 2018 1:19 pm

ok so i posted this question separately, or at least part of it, but it is applicable here also.
long story short. ran over a big plastic bag that wrapped itself around my rear axle. ABS, VDC OFF and SLIP lights came on. cut the plastic off but noticed that the lights all stayed on. went under and saw that there is a 1/4in gap where that metal toothed sensor is located as it enters the center box between the wheels.
no idea what that box is called, sorry.
what do i do from here?
safe to drive?
we got snow coming in my part of the country....is 4WD safe to use?

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smj999smj
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Postby smj999smj » Fri May 04, 2018 11:48 am

I'm assuming you are referring to the differential in regards to the "box between the wheels?" See part code "38300" on the part diagram linked below:

https://www.nissanpartsdeal.com/parts-l ... m=380_A003

A picture would be helpful, because it's hard to determine by just your description whether the ABS ring became dislodged or the flange has moved out of the diff. If you can't post a pic, you should probably have a mechanic check it out.

palo
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Postby palo » Tue Aug 28, 2018 2:23 am

Some of you are referring to a central diff in the Pathfinder but actually there is no central diff in the transfer case... only the multiple disc clutch for Auto and 2-4 sleeve for "hard" connection for 4H and 4L.
The AUTO system is more resembling AWD Haldex system as it is operating in a similar way.
But it is simpler then e.g. systems in Land Cruiser or Jeep Grand Cherokee as they have a real central diff with locking functions.
Everything is nicely explained in the service manual.
And who has a version without the AUTO, the system is the same as in Navara/ Frontier pick up truck.


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