Recently I went down dirt road with some big bumps. My truck was jumping all over the place. Anyways, later when I got back on the main road I noticed that my transmission would shift hard. Later, it was fine the shifts were smooth. Now it is starting to do it again. It doesn't matter what gear it's in when it shifts I can feel the truck jerk forward. I have no idea what it could be I might need a new trans. Any Help?