New Sound/Rattle only in "D" or "R" at idle- Can you identify it?

[Flash Runner]

Alright folks, This is my first time back in a while and I'm in need of assistance! I've tried the search feature, but to be frank I'm not really sure what to even search for regarding this sound. Any help, or ideas as to what this could be would be great!

The specimen: 2007 Limited 4x4 w/ V8 - 210k miles

Context: A little rusty in the undercarriage, spent first 160k miles in NY, but the frame is still solid so it's not that terrible.

The problem: I hear a rattle like noise, as if two pieces of metal are clanking/vibrating together and coming into contact. Based on my ears, it seems to be on the drivers side undercarriage, but I'm not sure. Here's the gimmick: this only occurs when in "Drive" or "Reverse" AND at a standstill. (i.e at a red light, stop sign, in the drive thru). The second I hit the accelerator, or shift into neutral it stops. I have a faint recollection of this occurring a year or two ago, but it lasted a week and stopped before I could check it out. Anyone have any ideas? I'm hoping this isnt transmission related.

Thanks in advance for the help! I'll try to upload a video of the sound when I can.

 

[AuSeeker]

Check the exhaust heat shields, they can sometimes get loose and rattle.
When in gear and not moving there's a bit more vibration in the drivetrain then when moving in gear which can make a loose heat shield rattle.

 

[TheV6ThatCould]

The description sounds very much like an exhaust heat shield issue.

A far fetched second idea is possibly a rotted out line slowly leaking causing transmission fluid level issues.

But really, I'd bet 99% chance it's a heat shield.

 

[702tripgen]

Yep, like already stated it sounds like a thin piece of sheet metal. Get under there and start banging, pulling, and pushing in stuff until you figure it out. If you can trust someone to put their foot on the brake where you get under there or at least on the side of it with your ear under there to duplicate the sound it will be a lot easier to pinpoint.

 

[Flash Runner]

[MENTION=149207]AuSeeker[/MENTION] [MENTION=643350]TheV6ThatCould[/MENTION] [MENTION=298259]702tripgen[/MENTION] - Thanks for the input guys! Seems like I'm trying to get under it tonight to inspect then for a loose heat shield, or anything else. Idk if I have a person I trust, but a big ole brick would never betray me right?:eyebrows:

I want to note something else I noticed last night when I parked, the sound got louder when the wheels are turned and not straight...

I'll come back and update with results, and if its not fixed I'll try for a video of the sound.

 

[UrbanRunner651]

If you got rust, check the connecting points on the exhaust itself rather than just the shields. It is noticeable in gear because of the low RPMs that shake the system. Turning could just be the pump adding more vibration, or opening up the wheel well more, amplifying where the sound is coming from.
Welds around the front & back of the muffler are common failure points. I had one on both the back of my muffler and then later the tabs off the back of the main cats. Both were hairline cracks that were almost impossible to see. I would only hear the rattle in reverse or stopped in gear.
I was also getting the mysterious "burning plastic" smell in the passenger wheel well after long trips which helped my isolate the first location.

 

[AceSpades]

Subscribing... I have the exact same rattle for over a year now, ive already gotten underneath looking for a loose heat shield with no luck. And youre right it seems to get louder when turning the steering wheel slightly

 

[Zero0575]

I had a rattle that only presented itsself in D or R at idle as well. Mine turned out to be the muffler coming out the rear - it was contacting a part of the hitch. I just noticed it when putting on my new Gibson catback exhaust. No more rattle

 

[Piggity]

It's going to the heat shield on the drivers side coming off the left bank of the engine.

The reason why the noise is louder when you turn the steering wheel is because the power steering pump idles up the engine more to compensate for the added load.

 

[PNW_T4R]

Did you ever figure out what the rattling was? Mine is doing the exact same thing, and I'm positive it's coming from the transmission. Sounds like it's coming from just behind the pan.

 

[Flash Runner]

Did you ever figure out what the rattling was? Mine is doing the exact same thing, and I'm positive it's coming from the transmission. Sounds like it's coming from just behind the pan.

Yeah - my heat shields were practically about to fall off as is, but also had a lot of issues with my exhaust system as a whole. Ended up replacing the whole system (as I had the manifold tick from cracked headers as well). DT Long tube headers - Y-pipe - Gibson Catback.

Also to note, prior to fixing exhaust but after removing the loose shields, I put in a few 12+ hour road trip days in a short time frame. I did notice heat coming into the cabin under the passenger seat.

 

[Gamblin4Runner]

Exhaust Hangers

I have had to check and adjust the rear-most exhaust hanger twice, now, due to a rattle.

Damn Thorley headers and Gibson exhaust just shake the h*ll out of it, I guess

:couch2:

 

[adammsu]

noise recorded

i have a similar noise that the people above have described... 2006 v6 224k. the alternator is pretty new, did PS pump, pulleys/tensioner are new... maybe it is exhaust, i will look again. you can hear it change a little with wheel input, or at the end when i put it in park it stops. are you guys hearing the same? its a pain to diagnose since it seems to be worse after its all warmed up, and in park it goes away, and its even less or gone when off the break... so hard to diagnose... the worst as i pull into the garage, which is below, or at the mcdonalds drive through - since the building reflects the sound perfectly....

give it a listen - thanks for the help!

IMG_0305.MOV - Google Drive

 

[shiftmx]

i have a similar noise that the people above have described... 2006 v6 224k. the alternator is pretty new, did PS pump, pulleys/tensioner are new... maybe it is exhaust, i will look again. you can hear it change a little with wheel input, or at the end when i put it in park it stops. are you guys hearing the same? its a pain to diagnose since it seems to be worse after its all warmed up, and in park it goes away, and its even less or gone when off the break... so hard to diagnose... the worst as i pull into the garage, which is below, or at the mcdonalds drive through - since the building reflects the sound perfectly....

give it a listen - thanks for the help!

IMG_0305.MOV - Google Drive

I just went through this. Check all the usual suspects first...loose heat shields, exhaust connections, etc. A good way to trouble shoot is to warm up the 4runner to operating temp and get someone you trust to sit in it with their foot on the brake and the trans in R and listen for where the sound is coming from. I found my vibration was from a loose airbox that holds the air filter. Once I tightened it up, the rattles are all gone.

***Let the 4Runner get to operating temp before trouble shooting because when in R, it will drop the the lowest RPMs that will produce the vibration. It will not do this with a cold engine.***

 

[adammsu]

I just went through this. Check all the usual suspects first...loose heat shields, exhaust connections, etc. A good way to trouble shoot is to warm up the 4runner to operating temp and get someone you trust to sit in it with their foot on the brake and the trans in R and listen for where the sound is coming from. I found my vibration was from a loose airbox that holds the air filter. Once I tightened it up, the rattles are all gone.

***Let the 4Runner get to operating temp before trouble shooting because when in R, it will drop the the lowest RPMs that will produce the vibration. It will not do this with a cold engine.***

thanks for the idea! i was coming to the same conclusion actually, its a very low RPM condition. cheers!