i have a 2008 mazda3 hatchback with 7200miles(manual trans). I park the car in reverse in the driveway (which is a mini hill)without the parking break and the car started to roll ( it Took about one step and stop, then started to roll again) I then tried 1st gear and the same thing happened. It did not do that when I just bought it a few months ago(august 2008). Is that normal?
It’s normal. The engine has broken in and is probably not as tight as when you bought the car. You should NEVER use the transmission as a parking brake. If you own a car with a manual tranny you should ALWAYS use the parking brake to keep the car from rolling. In cars with rear drum brakes the parking brake is also used to adjust the rear brakes. Failure to use the parking brake will result in poorly adjusted brakes in those vehicles.
In all cases a parking brake that is not used will eventually corrode and “freeze”. Then you will not even have the option of using it.
knuckles is correct on all points. Most important is never rely on the transmission (manual or automatic) to keep your car in place when you park it. NEVER!
Always use the parking brake. Use it or loose it.