April this year, my wife and I purchased a certified used 2006 Chrysler Pacifica with AWD (we specifically purchased an AWD because of the snow we get in WI). I kind of have suspected that the AWD wasn't functioning correctly because very early on, when the pavement is wet, or slick the front tires would spin from a stop (I thought it was possibly the worn front tires, so I replaced them about a month, or so ago)... Anyway, this week we finally got som snow, so I could really test the AWD out... When we came home and pulled into the driveway (our driveway is fairly steep) we got stuck in the middle... So I opened the door to see if the rear wheels were engaged- only the fronts were spinning... Any ideas? I should also point out (I don't know if it's related or not) that when driving, when you hit 40 then again at 60, you feel and hear a very low vibration (I thought it was the tires, but they were replaced) almost sounds / feels like a bearing. Also we've had AWD vehicles in the past and have another 4WD that we use at time- I don't ever remember having any issues like this... Thanks for the help.