I have had no problems really with the car until about 5000 miles ago, I currently have 62000 miles. I know that the G is prone to having rattleing noises, but im hoping not all of them are going to sound like this. Im going to explain this the best i can as you know its hard to explain a rattle noise from the car.

When i start up the car everything is fine no check engine or transmission lights stay on. When i reverse out of the driveway everything is fine as well. I can go down any main road and everything will be fine. When i get on the interstate to go to work or come hope its when all of this starts. I usually get up on it when i get on the freeway and floor it from around 50 to 85 to get up to speed. When i get up to speed (cruising at 80-85 mph) you can feel the shifter vibrating and my it my foot is on the gas just resting you can kind of feel a gas peddle rattle as well. After i have drove for about 5 seconds on the interstate every little bump that i hit it feels as though something thats metal is loose(something heavy) and hitting something else thats a solid part of the car. Now it will happen at all speeds after i get off the interstate.

When i get off the interstate and come to the light to head east (turning left) i stop at the light (we usually stop on red down here) then go.. when i start turning left the noise will happen again (this doesnt happen as often when turning right) as soon as i get to around 4000RPM the noise sound like a grinding noise (almost like the drive shaft is spinning against something) now this will happen wherever i am on the road at just about any speed or gear...i notice it alot at the end of 2nd gear and end of 3rd gear while im driving in tiptronic. Whenever i hit a bump in the road after the interstate it soundls like my exhuast is commming up and the slamming back down on something metal. I cant seem to pin point the location of the noise..sometimes it sounds like its comming from under the center console part and sometimes it sounds like its comming from the rear of the car. The car accelerates fine and stops fine, but if i downshift in manual mode the rattle noise becomes pretty intense and will happen around 4000 RPM -1000 RPM without touching the brake this is all engine braking.

Im not sure if this is one problem that just sounds different in different situations or if its multiple things that are wrong.

Any information on this at all will be awesome if you need something specific ask and i will reply in more detail.