Strange Sound Coming My Truck

Hi all, I've got a 2010 Access cab 2tr manual 4wd. Whenever I'm driving at ~1600 rpm there's a buzzing/grinding sound coming from the underside of my truck (I think, as it's hard to pinpoint while driving). It does not do it when the truck isn't moving, it does it very consistently, whether the truck is cold or warmed up although it is louder when cold. I've checked the usual culprits (heat shields, etc.) and haven't found anything. Any help is appreciated.

 

Id double check that heat shield that is on the exhaust. Mine was tight when I messed with it but I still had a buzzing. Then decided to lace it up to snug it more and the sound went away. Maybe your skid plate bolts are coming loose causing a vibrations?

 

Does it happen louder when you let off the throttle?

 

Sorry it took me so long to reply guys. It does not get louder when I let off. I'll have to try putting some safety wire around the heat shield.

 

I'd take a strong look at your catalytic converter.

 

Do you mean the heat shield around it or the guts of the cat?

 

The guts. Mine failed at 12k miles and @Poe has had 2 cats fail and he is probably under 30k miles. Both are 2.7s. Both had rattles like you describe.

Just something to check into.

 

Ok, thanks. Did yours throw a code?

 

No codes for me. I don't know about him.

I assumed mine was a heat shield. It got significantly worse as a week wore on before I could take it in. The honeycomb guts of my cat had fallen apart and were rattling around, same story for @Poe.

 

Wow, that's fantastic. Maybe I'll buy the o2 sensor simulator from urd and punch out the cats.

 

Or get it replaced for free.

Fed govt requires cats to be warranties for 8 years and 80k miles IIRC

 

Ya but... No cats is better than two cats. Unless you know otherwise. I'm not sure what the drop in back pressure would do with our engine.

 

I have to have cats here so it isn't a consideration. Just tossing out options.

We aren't even sure it's a catalytic converter issue you're having!

 

This is true, my friend, but honestly it's a why not kind of thing. Pennsylvania isn't nearly as restrictive (although I am still supposed to have them), but they don't check it if there's no light. I'm honestly hoping that's what it is. I've been living with this stupid buzzing for months and it's slowly driving me to insanity.

 

When mine buzzed at that rpm it was the heat shield on the cat. It was loud and annoying. My dad had some old old asbestos sheet from who knows where and I cut some strips to insulate the shield halves from each other and the pipe. No buzzing since. That was at least a year ago.

Before you go taking your cat off the truck, try removing the heat shield and driving for a little bit, see if it goes away.

 

Absolutely nothing.