For the first time I drove on a thick layer of slush this week.
The car was fine, but about a a quarter way home, I heard a loud noise like someone raking their finger nails across a blackboard.
I was only going about 20mph on a flat surface, when it first did it.
The other 2 times was on a slight downhill grade.
I was not using my brakes in all 3 instances, just coasting.
It last about 5 seconds, and did it two more times over the span of 15 minutes.
However, for the next 45 minutes and since then, it has not done it.
I will have to see this Thursday and Friday when it snows again if I can duplicate.
Sounded like a train when it comes to a stop and makes all kinds of metal screeching brake noise.
Like I said, it has not done it since...
Any ideas?

 

Make sure your car has the lower engine cover on it. It bolts to the middle of the subframe.

Sometimes if the car doesn't have it and water/ice gets in there it will make the belt slip.

 

sometimes when i accelerate on the slush and it slipps, i get that raking sound, and its always my STC, or the traction control.....

 

I too had this problem and took the car in. Apparently there is a TSB on this. Snow building up on the exhaust and weighs it down pushing it up against the driveshaft. They installed a 'spacer' kit and it went away. This may be your situation.

Regards,
Alex
2004 S60 2.4T