Something loose??

[SRSRunner]

No im not talking about the sound when I shake my head...
I've got something loose in the rear of my truck- can feel it while going slow through bumps and also a slight metal to metal type of sound while at a higher speed.. What or where can I check- I've checked the wheels, shocks and control arms. I do not have a rear sway bar. Everything I checked was tight- bushings seemed ok. So what am I over looking?
If youve ever had a shock break or come loose its basically that same knocking sound.

 

[brian2sun]

Check the tightness of your pan hard bolts.

 

[SRSRunner]

checked that- wasnt the issue. From the sound i figured it was either that or a shock but now im stumped as neither are the problem.

 

[brian2sun]

Lay under the truck and listen while you have a buddy post his foot on top of one of the rear tires. Have him shake the truck with the power of his leg. This works better than just shaking the body because the motion is coming from the tire as opposed tocoming from the body above. Hopefully you can pinpoint the noise that way.

 

[SRSRunner]

right on, ill try that in a few- thanks

 

[the great him]

exhaust knocking against something?