I have a 2002 H6 outback wagon. First time this happened it was snowing and road condition was snow covered. At 85-90 kph (canadian). I developed a sway in the car. Not a tail wobble but the car sways and rolls side to side to a point of scaryness and you have to oversteer to compensate, could not drive any faster. Dealer said that ice may have built up underneath and locked up the suspension. After washing the car the sway disappeared. Maybe they were right. the other day I drove into the same condition and after driving at 115 kph for about three hours I developed the sway again. couldn't drive faster than 80 kph ( too scary). I went a dealer again, same comment. ( Hey Guys, this is a subaru, it's for driving in these conditions!). When this happens, sure the roads were slippery, but a little embarrasing being passed by mini vans doing 100 kph. I've had the car checked out by a dealer and nothing is out of wack underneath. (suspension,ball joints, tire pressure, new tires, alignment,sway bar, shocks, etc.) I have a 1997 & 2001 outback as well and this has not happeneed. Any Help Out There?:-\