I've had the car for 6 years, it's an automatic. Today when I tried to shift out of park I really had to pull hard and it sort of snapped into reverse. Once it was in reverse I could go into drive and back into reverse and even back into park with no trouble. But once it was back in park it was a struggle to get it out of park again. Wasn't like this this morning, just since about an hour ago. How serious is this? Anyone know what caused it?