does anyone know how the auto-4wd works? it says in the manual that 4wd is automatically engaged when vehicle senses loss of traction. i'm wondering if it gives ANY extra traction the rest of the time. for example, when hiway driving, will it do anything to prevent loss of traction, or will it wait till i'm going sideways into the ditch to kick in?


07 black SLT 4x4

 

I can't speak specifically about your truck, but the way most others work is that the truck is 2wd until the wheel speed sensors detect one wheel turning significantly faster than the other indicating that it has lost traction. At that point, the clutches in the transfer case engage and shift some power to the front wheels until rear slippage stops. I have never seen a system in a truck with a yaw sensor that would detect that the truck is about to go sideways and compensate.

 

Yaw sensor would be inherant with traction control for handling, IE: Mercedes, Corvette....

Ford's auto-4x4 monitors the system 60 times a second, for auto-4x4.

If a wheel sensor noted a wheel spinning faster (rear over front, or visa versa) then another wheel, the 4x4 is initiated until the sensor speeds match.

Engagement can be either through the transfer case, or through a swith that activates the front axle. Either way, it kicks in and out as needed.