how does my awd system work?

[Newyork1267FM]

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[Curtis]

Someone may correct me (or add more detail) but I believe the AWD explorers use a complete mechanical way of distributing power.

The front has some power all the time anyway 10% mayby - but when wheels start to slip, there is viscous coupling that gets out of sync. Because both sides (front/rear) of this coupling are now turning at different speeds the fluid in it instantly becomes a solid and locks the front and rear wheels for 50/50 power

I read about a couple guys here where a guy with AWD didn't want it and a 2wd guy wanted AWD.
They swapped running gear since no electronics are involved in the AWD system it was an easy swap and no computer or wired problems to deal with.

 

[Newyork1267FM]

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[Curtis]

Probably so... I wasnt sure on the numbers. but at least you know the basic concept of how it works.

 

[jrford]

with my '04 AWD, all 4 tires spinning while on the hoist, just at idle in gear.
You should also have open front and rear diffs which can allow only one tire to spin, but at least the front and rears spin.

I thought when you got stuck and the tires start spinning, you should get a full lock, or you should pull out. How many miles? I hate to say it but it sounds like the viscous clutch is fried. One of the test is put the front or rear on ice and you should still be able to pull yourself out. What happens when you drive in a slow figure 8? Any binding?

 

[Newyork1267FM]

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[JCat]

Read this first and then come back and ask questions: http://en.wikipedia.org/wiki/All-wheel_drive

 

[Newyork1267FM]

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[Curtis]

I think your truck is performing normally.
I'm sure that you don't have posi axles front and rear so one tire spinning is normal
Which ever wheel has the least resistance is the one that's going to spin.

My 04 4x4 has a posi rear so I would have 3 wheels with power

I think on a hoist all 4 would spin just because there is no resistance. I bet you could hold one and the other side would continue to spin.

 

[JCat]

I have a 1978 F150 4X4 that has a transfer case that allows you to lock the front and rear output so that the front and rear DIFFERENTIALS get the same power.

When I first got this truck, like you, I jacked it up and discovered that only 1 rear tire and 1 front tire turned.

I quickly learned that unless your drive axles have the OPTIONAL "lockers" or "limited slip" differentials, that this was all I could expect. I quickly upgraded both differentials to a locker in the rear....and a limited slip in the front.

If you do not have lockers or limited slip, you can use the parking brake to insure both rear tires get equal power when you are stuck. By applying the parking brake, you are fooling your differential into giving both rear tires power. This is a trick that only works some of the time.

My 1998 Mountaineer came with a limited slip rear end .....it was standard equipment then.

 

[jrford]

here is a write on an earlier version of the AWD.
http://www.explorerforum.com/forums/showthread.php?t=225515
hopefully it helps,