How about just take the tailgate off, and then drive around to see if the sound goes away?

 

Now thats a pretty good idea. I will give that a try. Thanks.

 

do you have a quad cab? on the older dakotas they had a "stabilizing bar" forward of the hitch. it fits into rubber gromets and when these wear out there can be a rattling noise.

 

I have a club cab

 

Do you have your spare tire under there and is it tight?

 

Motodeficient, I had a similar rattle and changed the rear stabilizer links and the noise decreased but didn't go away. So I was able to narrow it down to the shocks. When I had the truck up on jacks I was able to recreate the noise by pushing up on the bed from below. I removed the shocks and the noise was eliminated. So i need to get new shocks. In the meantime I tightened the bolts real tight and the noise is still gone. Hope this helps.

 

you might also check the exhaust hangers could just be your pipe bouncing against the frame or the body....

 

so whats the verdict did it go away or not?

 

This was my first though on diagnosing the problem.

 

I haven't really looked into it. I have new ranchos on there so I don't think thats the problem. I will get back with you guys once I get some time to investigate. Thanks!