4WD: Binding the drivetrain

I let my girlfriend take my truck to work since it was icy out this morning. I was explaining to her about how when using 4WD you shouldn't turn the steering wheel all the way to the left or right to avoid binding the drivetrain because the front wheels are now engaged with driving power.

Then that got me thinking....with FWD vehicles this doesn't happen yet their front wheels both steer and propel the vehicle. At first I thought it had to do with the differential but I know the Tacoma has an open front diff.

So what's different in a FWD vehicle that allows the front wheels to be turned without strain to the drivetrain?

 

a differential

when in 4wd, there is no center diff... it is locked. the binding is front to rear, not side to side.

 

AWD vehicles essentially have an open diff in the transfer case, your taco does not.

 

Interesting. So things like Subaru's and such get away with this by the center diff?
So really the binding is happening with the front and rear inside wheels wanting to cover less ground than the front and rear outside wheels correct?

 

Yep.

No, the rear wheels want to cover less ground than the front.

 

checkout the signature links below...

 

How so? The right rear wheel is still on the inside of the turning circle so the distance covered MUST be less than the outside.

EDIT: Ahh but there's an open diff between the left and right so that's fine. Gotcha, we're good here. I think I got it now.

 

Would it really matter if you turn the wheel all the way if your on snow or ice since the wheels can "slip". I would think in that situation it would be fine... Yes no?

 

Good question.

I'd imagine it's fine as long as you're in a slippery surface and the wheels DO slip. If you have enough traction that they do not you'll see ill effects I'd think.

 

It still kinda hops at full lock

 

Just get in the habit of never turning the wheels to full lock when 4WD is engaged no matter what surface your on.

 

Or, get a 4Runner with a center diff!

 

That's basically what I've done.

The thought has crossed my mind. I'd be lying if I said it hadn't.

 

The center diff is awesome for all of the slick rock and large sections of rock out here, allows one to stay in 4 and make hard turns, then straighten out and lock the center diff back up.