i was turning around in a parking lot tonight and was going down a hill when i went over a water main type deal. the lid of it was half cocked and when i went over it, it drug on the bottom of my car pretty bad. i stopped to make sure that it didnt knock a hole in my oil pan which it didnt. got under there with a flashlight and seen that it smashed one side of my h pipe but that was all i could see. now when i take off from a stop i can feel the driveline vibrate and chatter. it does it in second gear and a little in third and is less noticeable in the rest of the gears. what else could be fucked up that would make it chatter and vibrate? i jacked it up when i got home and nothing else looked banged up besides the h pipe. what else could it be???