kingkong

Hello. I am new to this board, and to the truck.

When we got snow last week, I parked the truck in front of the house.
The front passenger side tires were on top of a little mound of snow/ice that I shoveled earlier and the passenger side rear tires were on some snow too, but not as much as the fronts. The driver's side (front and rear) were on dry pavement.

I didn't think much of it and just left it there. Later that day, I switched it to 4WD-Hi and decided to move the car. No dice.
I asked my wife to see if all the tires were spinning, and she said that only the rear tire (passenger) was spinning.

She did not look at the other side though.

Does this mean my 4WD is not working? Or is it doing this because maybe it has open differentials?

If the rear driver's side tire (on dry pavement) was spinning, the truck should have at least moved a little, but that did not happen.


Thanks.




Vehicle:
1994 Pathfinder SE-v6 Automatic
It has around 145K miles.
30x10.5 15 tires

X-Traction

My guess is that the truck has automatic locking front hubs, which have to rotate up to one revolution before they engage. So if you weren't moving, you were left with 2wd.

This is why some choose to install manual hubs. If you get stuck without the automatic hubs engaged, you may not be able to move enough to get them engaged. This has never happened to me, but I can see how it would happen.

Next, I gather you either don't have a limited slip rear differential, or if you do, it needs servicing. So you sat there with one wheel spinning.

This is why limited slip rear differentials are so useful. Had you gotten the front hubs engaged, you might still have been stuck if, say, you were tilted uphill. You could then spin both tires on the passenger side. A limited slip rear diff. would also solve that problem.

The behaviour of 4wd systems can sometimes be quite puzzling, and hopefully someone will correct me if my comments above are wrong.

__________________
'91 Pathfinder SE 5spd (now sold)
'06 Suzuki Grand Vitara JLX-L

kingkong

Thanks! That makes sense, esp. about the front hubs.
Yes, I now realize the importance of limited slip differentials even more, and this
behavior of the truck makes me think that it has open differentials.

I will try to read the manual again, and see if there's anything that I might have missed about the 4WD.

This is a different animal, and obviously, I'm still learning.

X-Traction

And a limited slip will only grip up to a certain point of stress difference between the two sides. We sometimes go beyond that point when traversing diagonal ditches, so I've been looking for something with full traction control. People who are ok with sacrificing on-road handling solve this by installing locking rear differentials, and even sometimes locking front differentials.

Given how cheap a limited slip differential is, I really don't understand why they're not standard with on-demand 4wd systems like our Pathfinders'. As you've found, the system has some huge weaknesses. Why bother to add so much gear to get 4wd, then leave it severely handicapped? I suppose the best would be lockable/limited slip differentials in all three positions.

In your case, it will be easier to make your rear differential a locker, since making it a limited slip will require replacing the rear axle. I'm glad I knew about this when I was shopping for the Pathfinder, and made sure I got one with the lsd.

For more bad news, you should research how to keep your automatic transmission alive. (Add third-party transmission oil cooler and bypass the stock one.)

__________________
'91 Pathfinder SE 5spd (now sold)
'06 Suzuki Grand Vitara JLX-L

johnnyhammers

Dead on. Good answer. It may have been worthwile to rock the truck, but if the wheels are just in the wrong place to engage, well, there's not much to do. This is exactly why I love to keep a Come-a-long in my truck. Just a little pull goes a long way.