just got a new XC90 3.2 AWD. Our driveway is quite steep. As I was going uphill two days ago I had to stop to move a fallen tree limbout of the way. Driveway was covered with icy snow. When I resumed trying to go up hill the car slid backwards into a snow bank. Pushed the "W" button but it didn't seem to help any. Right front & rear tires just spun. Nothing seemed to happen using the "W" button. No action with left side front or rear wheels. Finally got unstuck when I threw sand under all the tires. Why didn't the left wheels pull the car? What's wrong(besides that I didn't buy a real 4WD)?

A close reading of the manual will give you pause. The AWD doesn't work well at zero speed. Had you backed down to the street and restarted your climb, it should have worked.
4WD has locking differentials that work at zero speed, but are terrible when the car is moving above 5mph. So once you enter a ditch with your AWD, keep moving. Your XC90 was built to keep you out of the ditches, the 4WD was designed to get you out of a ditch. Notice how many SUVs are off the road when it is snowing!!

Klaus
--
The 164 has a new home, all I am left with are a 95 854T and a 98 V70R :)