Hey guys, I have a 2001 LE. It has Auto 4WD. I'm simply wondering how it works. I'm really actually kind of new to 4 wheel drive. I had a Subaru with AWD, and I know the wheel tolerances had to be the same otherwise it would burn stuff up. My friend has a Ford Expedition with auto 4wd which is kind of the default mode apparently. He was having this weird thing where the 4wd would kick in and kick off every once in a while while driving in normal conditions not slipping around and stuff you know? Well, he changed out all 4 tires at the same time and it quit doing it which kind of indicates that the tires were just enough different sizes that the system thought it was slipping and engaged 4wd? Does that sound right? How does the Nissan system work? It snowed really heavily last night, so I was thinking about taking it out of 2 and popping it in Auto, but I wanted to make sure I wasn't going to damage anything. See, I always have it in 2, and my rear tires are more worn than my front tires. I don't want to burn anything up by thinking it's slipping when it's not. When I turn it to Auto the 4 little green tires on the dash light up, but it still feels like it's in 2, will something else pop up there when it kicks it in 4 then? Or do I not really know when it's in 4 vs 2 in Auto? I love this truck. Gotta say its probably my favorite so far. I found myself off the road once in 2WD, thought I was really stuck, I grabbed my phone to call my friend and I remember 4LO. Haha! It climbed out pretty easily after that! I was stuck really bad. So far I have not seen a truck in action as capable as the Pathfinder. Quite remarkable.
Thanks!

I am not an expert here.
My understanding is that in 'Auto', when road is not slippery, system still powers only on rear wheels; when slippery, all four wheels receive power up to 50% maximum on the front wheels depending on conditions.

I only used 4Lo once in Reno where I got stuck. Snow was so thick that I couldn't even put the chain on. 4Lo got me out easily when I saw so many other people trying hard to get out.

Okay so long as you still have stock hubs (not aftermarket manual locking ones) just flip the switch to AUTO. The system is designed so that it wont hurt anything when it switches. Its kinda like a form of traction control. Basically when you are driving around in AUTO going fine and it senses a rear wheel slip, it sends power to the front wheels to help control spin and move the vehicle forward. You will feel the system kick in but its not going to hurt anything. I would use this for snow and some rainy conditions....I am one of those if you think you might need 4wd then you should already be in it guys...plus I have manual locking hubs so I cant use the auto setting anymore.

When I am in AUTO setting the lights for the rear wheels turn off and the 4WD icon illuminates. Is this correct?

The light labelled "4WD" should only come on for a few seconds after your start the QX4. If it stays lighted, it means there's a problem with the 4WD system. I've also never known the rear wheel lights to go off when in AUTO -- all four wheels should be illuminated.

Yeah I had a feeling my 4WD system was screwy. Transfer case?

I was thinking I should change the oil and filter on it.

MCNPathfinder wrote:My friend has a Ford Expedition with auto 4wd which is kind of the default mode apparently. He was having this weird thing where the 4wd would kick in and kick off every once in a while while driving in normal conditions not slipping around and stuff you know? Does that sound right?
How does the Nissan system work? It snowed really heavily last night, so I was thinking about taking it out of 2 and popping it in Auto, but I wanted to make sure I wasn't going to damage anything. See, I always have it in 2, and my rear tires are more worn than my front tires. I don't want to burn anything up by thinking it's slipping when it's not. When I turn it to Auto the 4 little green tires on the dash light up, but it still feels like it's in 2, will something else pop up there when it kicks it in 4 then? Or do I not really know when it's in 4 vs 2 in Auto?

Couple of things: If it's in 2WD, it will not engage the front wheels, no matter what the driving conditions (unlike your friends' Expedition).
Going into Auto 4WD doesn't mean it's powering all four wheels all the time either. It only delivers power to the front wheels when needed (like 01 silvapathy says). You can switch in and out of AWD while moving with no problem.
Personally, If the weather is looking a little iffy (rain, snow, etc), I run Auto 4WD pretty much all the time. Never had a problem.
BTW, that's what these trucks were designed to do, so why you would think that you would damage anything by running AWD is a mystery to me. Oh well.
The only thing not recommended is running it in full time 4WD on dry pavement. That can cause undue stress on the system, especially when cornering.

Thanks for the help! I used 4LO this weekend putting my boat in storage. Got kind of late end to the season there. I had to drive through a field to get the boat to it's final resting place. There was about 4-6 inches of wet snow. Not even a problem! Man I love this thing. Anyways, so putting it on Auto is essentially traction control then. I was thinking it might damage it because the way the Expedition worked was because the rear wheels were a smaller diameter than the front ones, the rear wheels were making more revolutions or making faster revolutions than the front wheels, causing the Ford system to think it was slipping, causing it to engage and dis-engage the 4WD system multiple times per trip. I figured that's not good for it and didn't want to screw up my system by leaving it in Auto when I could just put it in 2WD so it didn't keep switching out. Does that make any sense whatsoever? If you all think it doesn't work that way then I'll stop worrying about it and just leave it in Auto for the season.