For a long time I struggled to find the source of a rattle at the back underneath the jeep. I thought it was the shock mountings, tried to "fix" it to no avail. Today, while checking the underside after a rough road trip I moved/wiggled the fuel pipe feed, return and brake lines at the left in front of the axle where it clips into a plastic bracket approximately beneath the rear door. The bracket clips into the side of the chassis beam with one of those accordion type plastic lugs. Due to age it started to pull out and allow the bracket to rattle against the frame. For now I made a rubber spacer and pressed it on top between the chassis and the bracket. No more rattle
Maybe I will use something like RTV to attach the bracket to the chassis and still allow it some movement. Hope this is of use to someone.