can the cam box be removed without removing timing belt?

You may be able to get away with only loosening the belt, marking it VERY carfully to the cam gers and changing the gasket. To do so you will have to remove the timing belt cover and release the tension on the timing belt tensioner. This should allow you enough room to slip the timing belt off of the gears. Mak,e sure you mark the exact tooth that the timing belt corresponding notch matches up to or you could cause damage to the vehicle.