All-wheel drive is standard with the twin-turbo 3.5-liter V6 and optional on the 3.7-liter V6. In good weather, over smooth roads at modest speeds and when AWD is not needed, the system intelligently routes power only to the front wheels for improved fuel efficiency.
When driver input or road conditions indicate that slip might occur, the system sends power to the rear wheels to help prevent tire slip, for example on rain-soaked or snow-covered roads. Beyond providing more traction, AWD also improves handling by helping to reduce understeer, the tendency of the vehicle to "push" in a corner.
A myriad of inputs enables the computer-controlled system immediately to identify and react in as little as 16 milliseconds to changing road conditions and driver demands. The amount of torque sent to the rear axle varies depending on road conditions and dynamic needs.
Above is a published description of the AWD in the new 2013 MKS that will be available in the spring of next year. I'm wondering how much of that description applies to my 2010 MKS AWD 3.5L. Am I really driving a FWD vehicle while driving over smooth roads at modest speeds?
To answer your question, yes. Our cars are FWD with the AWD cutting in only as needed. Unlike a full time AWD.
On my SHO, the AWD part is "mostly" seamless, as when starting off on a rain soaked road, however a couple times, when I was already moving at a slow speed, and I had to floor it, the system took a half second or a second for the rear wheels to cut in. How do I know this? Because only on those couple times did I get "torque steer", and voilent torque steer at that. Once the rear drive cut in, no more torque steer. (happened to me twice). Does not happen if i floor it from a stop sign.