Thanks everyone, I think I got it now.
4x4 Auto - Only need to press to get from 4x4 hi or lo, back to Auto. 4x4 kicks in when better traction is needed, otherwise the "standard" is Rear-wheel 2WD.
4x4 Hi - Use only on extended wet or snowy conditions, such as during a snow or rain storm, and probably best at slower speeds (<30 MPH)
4x4 Lo - Probably best if you are stuck in mud, sand, deep snow, and need that extra power to get out. I don't two anything but I guess you may use this to tow a boat or another vehicle. Not sure about this.
Last thing I am not sure is the previous comment about 4x4 High setting, "the front wheels need to be able to spin when you are turning". Can you please clarify? Are you differentiating between a wheel spinning as opposed to normal rolling (due to forward movement)?
Thanks again all.
How to explain.....basically, your "locking" the axle together. You know how some cars or toy cars (or lawn tractors) will spin the right wheel when the left wheel gets jammed or stuck? That is because they aren't locked together.
When your in 4wd they are locked together. If you turn the left wheel a 1/4 turn, then the right wheel also turns a 1/4 turn. Now, a disclaimer on this, technically it's not exact. They make these drives a "limited slip" (ever hear that before?) That is, if you turn the left wheel a 1/4 turn, the right wheel will turn a little less or a little more that it.
That's the background. Here is what they mean when they say "spin when you are turning." To get totally scientific, take a tube or a water bottle or something and put it on the desk. Now imagine it's an axle and roll it forward a few inches. Both sides of the bottle made the same number of revolutions. Now roll it and make it turn right. The left side of the bottle made more revolutions than the right side. Why? Because it has "further" to travel than the right side. If that's the case, then how did the bottle roll at all if the left side had further to go than the right? Because the bottle "slipped" on the desk and the right side of the bottle moved slower than the left.
That is what limited slip is, it's slipping...to a limit...to allow the thing to turn. If you didn't do this then the wheels would "bind" and you would break something. Try to roll the bottle in a turn without allowing the right side to slip, the bottle will twist. In the practice of a vehicle it will happen even when driving in a straight line because roads aren't perfectly level, tires are worn different, air pressures, etc..all contributing to one wheel moving slightly faster or slow than another.
Now since dry pavement has very good traction (unlike your desktop and a plastic bottle), the limited slip won't work. That is why you use only on wet, snowy, dirt, icy roads so that there is a lack of traction to allow the slip when turning.
I don't know if I did a very good job explaining it, but there is my shot
