I know there are threads that address this and the heat shield and skid plate are possible contenders.

I pulled into the garage with all of my windows down and noticed a rattle from underneath- sounded like metal on metal (and sounded more driver side). Interestingly enough, it would start when shifting into D or R. I shifted in to R to back up and align myself in the garage and it rattles. Then after letting the 4Runner roll a couple of feet, I hit the brake and it stops. Roll a bit, it starts. Shift into D it starts, roll forward, hit the brake, it stops. Release brake it starts.

Had to run another errand later this evening. Same thing but not as distinct and more subtle. Any tips or start points would be appreciated. I just thought it was odd the braking reduced/eliminated the rattle in the first instance.

No mods, all stock. Only 2,450km (1,522mi) on the 4Runner.

Do you have the exhaust finisher? Mine worked loose and rattled - made me nuts for almost a week.

Would that be the exhaust tip (had to google it lol)? If so, no just bare.

One other thing I forgot to mention- I decided to really try out sport mode and see if it would shift automatically. I had it in first and floored it. Sure enough it bounced off redline and didn't autoshift (idiot). Anyway I pulled into my garage 5 mins later then noticed the rattle. Not sure if that would be related.

I'm currenty under the 4Runner banging (softly) around with the soft handle of a screwdriver. I feel like the rattle be the long heat shield above the exhaust pipe. One piece of it looks close to... Something? Floor of passenger seat? Not sure what I am looking at. No sign of loose bolts. My whole underneath is black from the undercoating... So that probably doesn't help.

I've broken $hit while beating on my truck too

Sounds like a heat shield, changes in rpm will make them rattle differently. Snug up the bolts on them and on your skids.

I thought it COULD be the heat shield, but I'm no pro at this stuff. I was banging on the skid plate too... there is a plastic piece on the rear-end side of the skid plate....I couldn't tighten the bolts on it at all, but it seems like there was some play off the plastic piece and the metal skid when I banged it. Anyway, maybe I'm just being picky. I tried a few bolts and they were as tight as could be. It was a really tight squeeze under there, so it was hard to properly assess everything, but I couldn't find a for sure cause.

I fired up the 4Runner before closing the garage to see if there was a rattle- nothing. Put it in R and rolled a few feet. Nothing. D, rolled a few feet nothing. The vehicle was still warm (a couple of hours from when I got home), but not hot... so perhaps vehicle temp matters. I will keep my ears on it to see if anything changes.

I had a similar problem with my '11 TE. Took it to the dealer twice to have them check it. I thought it was coming from underneath the vehicle somewhere. They told me it was the skid plates that were rubbing on the frame. I called BS, because it was tight and no movement. Took it back to the dealer a few weeks later and what do you know? The service technician said it was the rubber splash guard in the left front wheel well. Sure as sh*t, it was replaced and the problem eliminated.
The splash guard is held in place with some plastic "plugs" that vibrated like crazy causing the "metal on metal" sound. Hope this helps.

Hi JayceeP,

Whenever you put the truck in gear then it starts to rattle. Okay, that's only because the engine rpm changes when it's in gear, causing the loose metal parts to resonate. If it were my truck, I'd chock the wheels with a couple of bricks or something. Set the parking brake, start it up, put it in gear, and crawl under the truck with a good light.

There's no reason that you'll not be able to locate that rattle, cuz it should be rattling already when you climb underneath; according to your posted description of the trouble (you'll find it) Good luck!

rig, best regards

mine does exactly the same thing!

Thanks guys. I will look at both of these suggestions and see what I find (hear).

This is EXTREMELY POOR ADVICE!!! Please DO NOT DO THIS!!!

When I offered my professional, technical approach and advice, I explained my reasoning as well. Would you care to offer an explanation for your DRAMATIC WARNING?

rigtec

Your idea is good, but more safety needs to be taken. Maybe LIGHTLY back the truck up to a VERY solid wall first (and only test in (R)everse gear) while also putting the wheel chocks down. I just don't think it's a good idea to get under a vehicle without the drivetrain locked in PARK with emergency brake on.

Hi ATL4R,

I've worked for many years (upwards of thirty five), as a mechanic. And I get it, "safety first". The things you mentioned, are extra precautions, nothing wrong with that; I''ll often take some extra safety steps too if I feel I need to (tis' a judgement call).

Additionally, I could have advised by the book, telling the operator to "Remove both drive shafts before starting...", but I opted not to because my focus was mainly to help him locate the source of his rattle, not to instruct him in the importance of observing safety standards.

If I thought that the OP was incompetent, I might have advised him to take the truck back to the dealership, because the scope of the job is beyond that which could be safely done in the driveway.

With all of these extra safety measures that I opted not to discuss, being very careful was implied when I instructed to "chock the wheels" along with setting the parking brake. The advise that I offered still was not bad advise; not by far. Thanks again for your input.

rigtec, cheers

You told the dude to "Set the parking brake, start it up, put it in gear, and crawl under the truck". And this is your "professional advise"?? This is a recipe for disaster!! If someone were to follow this advice they risk serious injury or possibly death!

However you did show some concern...that he have a good light, yeah that'll help him see clearly that he's about to get run over.

And yes, by far, this was poor advise!