I've had this anoying rattle in the back of the 4Runner for a while now. I crawled under there to check it out, and I think its the spare tire. There seems to be alot of movement in the mount and I'm 99% sure that's what's causing it.

Any suggestions on how to secure it?

 

I have a similar clunking noise. I haven't had a chance to look, but I'm leaning towards I've got a loose exhaust mount.

 

The spare is spring loaded, so it slams back into the body when going over bumps.
I've glued some foam to the body, pretty much quiet now.

 

Cool. I'm glad to know that it's supposed to have some movement to it then. I'll try that foam trick!

 

For those who have hitches in their receivers, make sure this isn't what's making the rattle back there. That's what rattles on mine.

 

maybe yes maybe no-
after checking my tire, looking for loose scrap metal rolling around on the under carrage, I'm now starting to think it might be my tail gate. I know the two suppots that keep it from falling past horizontal make some of the noise I threw a rubber wedge in each side and some of the noise was gone I'll let you know if I find more.