When i shift out of park, regardless of what gear i am going into, i hear a loud thump. It's not only when i shift out of park, but when i go from reverse to drive and so on, however, it doesnt happen when i shift from, say, Drive to 2nd (which is understandable).

My question is, what is this problem, does it pose any real risk other than an annoying noise (will the trans drop out of the car, lol), and if it does pose a risk, what is a realistic estimate to get it fixed?

Thanks in advance