[01tj]

I crawled under my truck today an d noticed a cylinder bolted to my exhaust. Anyone know what it is? I'll try to post up a picture

 

[upflying]

I think that is a harmonic vibration dampner.
Something vibrated during the engineering of the truck. That cancels out the vibrations.

 

[mtyler11]

I think that is a harmonic vibration dampner.
Something vibrated during the engineering of the truck. That DAMPENS out SOME OF the vibrations.

^^this. If you replace your exhaust, you can lose it. And it does nothing for the vibration of the heat shield.
If you happen to lose it to rust or rocks, don't sweat it.

 

[tumbleweed]

I took mine off when changing out my exhaust and run without it for a while; then one day I had the truck up on my lift and put it back on. As mtyler11 posted above, no difference.