[ASO544]

I have a new CSX 6000 car with less than 700 miles on it and have been chasing a rattle /knocking since day/mile one. The rattle /knock seems to be chassis related as it only makes noise when going over bumpy areas or when the chassis flexes and it has a metal sound to it. It does it when under power or when coasting ( in gear or out of gear).

I also get a couple of popping sounds from under the car when I push the car out of the garage ..... which I usually do to keep from killing the family with the exhaust : )

I got under the car and checked the usual suspects

1. Drive shaft is tight with no play
2. Rear end seems tight
3. Tranny is mounted tight
4. Side pipes are tight
5. Parking brake cables are zip tied to minimize movement
6. Wheels are tight
7. Battery behind passenger seat is mounted tight
8. Seat belts where they attach to the body are tight
9. Trunk lid is tight and I removed the trunk lift rod just to see if it was the culprit and it wasn't.
10. Rollbar is tight
11. Electric fuel pumps a tightly mounted
12. Seats are tight and no movement.
13. Gas cap is tight
14. Tail lights are tight
15. Tags mount is tight
16. Jack lifts are tight
17. Aluminum wheel well close out panels are secure.

The one thing that has me concerned is the rear end was replaced under warranty during the power train install as it had a loud howl. Im wondering if something wasn't secured properly on the install but everything looks and feels tight and there is no tell tell "thunk" you usually get with a loose pumpkin. Car drives great.

My other concern is I can only check the car when on jack stands and the suspension is full flexed so that may be hiding the problem.


My next move will be to remove the rear tires and check the rotors and calipers just to cover that possibility but feel they are good based on how the car drives and stops..

My other thought is the fuel tank. Maybe it's loose inside the rear housing as I not sure what actually secure it to the chassis. I also noticed the two large bolts that you can access from the access plates in the trunk....are those for the rear end mounting?


Any thoughts or suggestions will be greatly appreciated? I'm sure it's gotta be some thing simple and staring me in the face.