Metallic noise when taking off from a complete stop

They are also there to prevent starting a fire under your truck when you park over dry grass...

 

But they are above the cat, not below

 

They are there for heat soak into the cab area of the truck, the ones mounted above them anyway...so you dont get "hot spots" on the floor of the cab. and they are not all that critical at all. I have removed mine due to corrosion issues, and I dont worry about heat soak as its usually effing cold here anyway...

 

Thanks. I would replace it, but the damned stud broke off when I tried to remove the nut.

 

yep...happens to all of us in the rust states(mine broke as well)! Some people drill and tap for new bolts, so theres always that. Depends on how much time you want to invest in it