I know this is an old thread but I just wanted to say "Thank You" for the suggestion to check the mudflaps. I bought my Pathfinder used and it's had this rattle when driving over/around 70 MPH since the day I bought it. It sounded like it was coming from inside the door, so the dealership I bought it from completely disassembled the door twice and put it back together but it never fixed the issue. I decided to dig around on the message boards and came across this page's mudflap suggestion, had my dealership check them this morning and several clips were missing. I didn't hear the sound on the interstate when I left the dealership, so I'm hoping that's the end of my rear passenger rattle. Thanks again.I had almost the exact same situation/sound. Nissan tech identified it as the rear tire front deflector missing a clip and flapping in the wind at high speeds. Drove me nuts but is fixed now.
That is why we never retire a thread. There is lots of good information here....the collective wisdom of all our members since late 2012.I know this is an old thread but I just wanted to say "Thank You" for the suggestion to check the mudflaps.