Catalytic Converter Rattle Anyone?

Hey guys, during my ride home yesterday ( on pavement ) my truck developed a clattering noise, like metal slapping metal....I poked my head around and it sounds like it's coming from the front catalytic converter-- I noticed a dent/depression in the side of it that doesn't look like it should be there, however it's on the side of it that my skidplate mostly covers. The dent also doesn't look new--there's plenty of caked on mud and dirt.

Has anyone else experienced this noise before, and can anyone post pictures of theirs to see if the dent is supposed to be there?

2019 TRD O/R MT

 

I've had heatshields cause all kinds of racket on all kinds of cars. When it cools off, bang around under there and you should find it quickly.

Edit: mud and dirt you say. Think there's a stone on a heatshield? I have one in my RS' cat shield that I can't get out and its pissing me off, lol

 

As Doobfucious said, hit stuff with a rubber hammer and you should find the noise quickly. It’s prob a stone rolling around on the skid plate or above a heat shield....
As for the cats, if you did hit something hard enough that the material inside has broken up, you’ll know when you hit it with a rubber hammer and hear the rattle. Although it’s not usually a ‘metal slapping’ noise like you described..

 

I had the same issues with collecting stones or the welds on the heat shields broke on my 01 tundra. Tore those heat shields right off...no more rattling.

 

I had the same noise on my 2nd gen and it was one of the bolts that attaches the tailpipe section of the exhaust to the cat. It’s a bolt with a spring on it. It was up against the metal flange of the exhaust. Just pried it over a little with a screwdriver and noise was gone.

 

I’ve had my Transfer skids plates bend into the driveshaft? Could be the heat shield as mentioned above.

 

Took a peek at the heat sheilds, knocked on them a bit. No change, no rocks fell out. It did not make the noise when I started it, but when I parked it was making the noise.

Makes me think it's definitely the cat. No idea when or how the dent got there but seeing it in daylight I'm certain it's not from factory. It's in a spot and direction that there's no conceivable way it could be caused with the skidplate there and intact....so it must have happened when I first got the truck....

 

I'm going to wait for it to cool off and I'll take a peek at those

 

We don't have a spring.

If the substrate in the cat is somehow loose, it's 100% a warranty claim under emissions, that has an 80,000mi warranty, i think. You'd probably have a CEL/P0420 code for that though.

 

Is the shroud loose at all? I mean AT ALL. Even in just a corner... when that mother bitch heats up, the metal flexes and it’ll vibrate.

 

I made sure it was on tight. Even went and held it still while it was running and the done persisted and did not change.

The dealer I go to is really amazing about putting stuff under warranty, but I'm concerned that this one's too obvious not a factory defect given the dent.

 

I had a GMC Sonoma that developed a rattle in the Cat. I assumed it was from an internal tack welded baffle that broke at the weld. Traded it in and never found out.... So ,, If the Truck is still under emission warranty - I'd have the dealer check it out .. JMO

 

If they won't warranty it I'd leave it until you get a code. I had an Explorer that had cat rattle (no dent) and drove it that way for 150K miles with no issues.

 

amazingly it solved itself after a long road trip.... Think I'll take @RX1cobra's advice and leave it until it causes an actual issue. Don't have to get smogged until next year anyway

 

i would wash that dirt off the cat. That thing gets super hot plus dry mud is more heat.