07 NNBS 1500 rear end rattle

[SideSwipe]

Over the past year, my truck has developed a problem that the GM techs can't really replicate and explaining the problem to people is a little difficult. I need to start printing the story out and handing it to people. Hahaha. Truck has about 71,000km (~44000mi).

 

Anyways, to the problem. My truck has a strange rattle which is quite difficult to pinpoint. And it isn't just a rattle (like an exhaust rattle), it's more of a clumping-metal shearing against metal sound/rattle. You'd know the sound if you ever scraped two thin pieces of stainless steel together at 90 degree angles. That kind of sound. Sorry. That's the best I can do.

 

Only happens when I go over bumps (like a parking lot sized bump or larger), sometimes straight on, sometimes when turning (but If turning 90% of the time happens turning left). Speed varies, not exactly sure, but it's faster than a crawl. ex: going camping, the roads are kinda rough, speed limit is 35kph or so. I don't jump the thing or bash it around, or drive it aggressively.

 

Sound defiantly comes from the rear and driver side (99.9% sure driver side. Might be passenger side, but my passengers usually tell me driver side when they hear it).

 

I spent hours under the truck looking for loose or sheared bolts, cracks, etc. Can't find anything. I don't see anything wrong with the leaf spring(s), but It could be a shock (?). Rear end isn't leaking, no leaks near the input to the diff. It isn't the exhaust system moving on the hangers either. It isn't the tailgate, but sounds to be box related (?)

 

For a similar sound, Watch the UK Top Gear Amazon special. When Hammond is driving on the dirt road with the FJ, the sound is similar but not that frequent. Only on biggish-more jarring bumps--- like a pot hole kinda bump.

 

So, GM Forum Techmeisters... throw me some ideas what this could be.