There is no extended car scene.

There is proof on the lost media archive, a user named Nevan made up the extended car scene and even provided a fake cel that is literally in the film.

Someone contacted Gary Goldman and asked him about it, and Goldman debunked the lie.

Unfortunately, many people still believe that lie, so I felt it was my responsibility to tell you all, it was a lie made up by someone who literally said the reason they made it up was because they were bored.

Sorry, but I just couldn’t stand seeing people believe this lie any longer.

As for the hell scene, I think it’s proof the uncut version of the movie still exists (and in good quality too! Even in open matte!). If only that tumblr user could tell us what the summer art program was. We should send Goldman on a search for this, the original cut of the land before time, and the original cut of rock a doodle.