I park my car in a driveway with a slight incline. Once I backed it in, once I pulled it in. Both times I have come out to see that the car has either rolled or slid from its spot. It’s winter and snowy, but need to know what to do to prevent this? Or is it something that needs to be addressed by Subaru?
Try cleaning your driveway of the snow and see if that solves the problem.
Also you should set the parking brake before putting the transmission in park.
Use a couple of wheel chocks on the downhill side, the don’t cost much.
Controlled Experiment Results
Is this the first car you or any others in the family have parked in this driveway in these conditions?
Of those vehicles, is this the only vehicle that suffers from this affliction?
If you have the car in park (or in gear if it has a manual transmission) with the parking brake on it’s probably sliding. If you have it in park without the parking brake on the transmission’s parking pawl could be allowing it to move. If you have it in neutral with the parking brake on the parking brake might need adjustment. Post back and let us know which option applies. Wheel chocks would help but shouldn’t be necessary IMHO.
Is it snowy or icy? Assuming your parking brake is on, I wouldn’t expect this to happen on a slight incline unless you’re on ice. Regardless, you probably want to keep a mix of salt and traction grit in a bucket and spread it around your tires when you park the car.
Out of curiosity, what tires do you have?
You could mark the tires w/some chalk to see if they are rotating or sliding?