My sister has an 07 Chevrolet Tahoe with an Auto 4WD setting. I’m not sure exactly how this system functions, but I do know that GM SUVs have had a similar system in place for the last 10 years. I also know that it works remarkably well. I had an opportunity to drive her vehicle during a recent snowstorm and the performance of the system was amazing. I saw little need for the 4wd High setting on the vehicle for the average driver (the 4wd Low is still advantageous when the vehicle is stuck and you need to crawl out of a situation).

A couple other comments.

Remember that there is very rarely a situation where driving on ice results in ZERO traction. Even in the iciest situations there is some traction and a skilled driver can maintain some control over the car.

Second, one of the big differences in FWD and RWD cars is the amount of control after the vehicle loses stability. In a FWD car ALL of your steering, power and most of your braking are controlled by the front wheels. If the front wheels slip there is little hope in regaining control of the car. In a RWD car the power function is in the rear wheels. In many situations, even if the front wheels slip and you lose steering and braking you will still have an option of applying power and using the application of that power to maneuver the vehicle.