I don't know if its a transmission problem or what however I have attached a video on what has been happening when I put my car in Drive. It sounds like something is shaking underneath my car. However when I put it into park or any other shift i don't hear it. Is my transmission going out? I've never flushed or changed my transmission fluid (its at 135k miles). I am very nervous on doing anything with my trans, that is why I didn't change my trans fluid.
In the video, I start off in drive then put in park then i tried Neutral and switched back to drive.