Can't figure out this damn rattle/noise

[Nottoday]

Hi guys!

Sorry to pat one of these "what's this noise" threads. Wife and I are leaving on a cross country road trip in less than a month and the truck just started making a very odd noise.

It's a 2000 sr5 v6 4x4 auto w/ 168k

The noise sounds like what a lose/rattling timing chain sounds like.

Obviously that's not the cause as we have belts. And my belt along with all the other belts and hoses where replaced 10k ago.

So the noise is a faint rattle that is only present under medium gas peddle pressure. There is no noise at idle or WOT.

The engine does not make the noise at all bein reved in Nuetral.

The engine runs smooth as ever.

The transmission is running smooth/crisp as ever. Temps are normal. Fluid is good.

No abnormal behavior or codes besides this noise.

I am also fairly sure it is not exhaust related as I have removed the heat shields due to a rattle months ago. And this rattle does not sound like that.

Thanks guys for any input you may have!

 

[kolelt]

These things are hard to diagnose over internet. Check your exhaust. Make sure it's not touching he cross member. And the heat shield check that to. Mine makes a rattle noise under acceleration and it's my exhaust slightly touching the cross member.

 

[phattyduck]

Put in a tank of 93/92/91 octane (the highest easiest available) to rule out pinging/detonation. It should get quiet(er) with higher octane. You may have a 'deaf' knock sensor that still tests well according to the ECU.

-Charlie

 

[Bandit Runner]

So the noise is a faint rattle that is only present under medium gas peddle pressure. There is no noise at idle or WOT.

Any updates? Mine is doing the exact same thing. Slight rattly noise only while engine is revving. Usually just before the trans shifts up to the next gear.

 

[JRZEE2000TR4LTD]

Hi guys!

Sorry to pat one of these "what's this noise" threads. Wife and I are leaving on a cross country road trip in less than a month and the truck just started making a very odd noise.

It's a 2000 sr5 v6 4x4 auto w/ 168k

The noise sounds like what a lose/rattling timing chain sounds like.

Obviously that's not the cause as we have belts. And my belt along with all the other belts and hoses where replaced 10k ago.

So the noise is a faint rattle that is only present under medium gas peddle pressure. There is no noise at idle or WOT.

The engine does not make the noise at all bein reved in Nuetral.

The engine runs smooth as ever.

The transmission is running smooth/crisp as ever. Temps are normal. Fluid is good.

No abnormal behavior or codes besides this noise.

I am also fairly sure it is not exhaust related as I have removed the heat shields due to a rattle months ago. And this rattle does not sound like that.

Thanks guys for any input you may have!

Possibly the substrate inside a catalytic converter has broken away from the inner walls of the converter.

 

[Kanoe]

Possibly the substrate inside a catalytic converter has broken away from the inner walls of the converter.

Mine has a slight rattle at about 1800 rpms and again at about 2600. I suspect it is this as I just can't find it. Only happens under load, not sitting in neutral. Oh well, someday I may find it.

 

[Koko4]

Mine does the exact same thing. Only under load, usually higher RPM's, and hard to reproduce while sitting still. It is the heat shield on the passenger side of my exhaust, in my case. Get underneath the truck and try to recreate the sound. I was tapping around with a screwdriver to figure out what it was. Had a friend rev the engine while I was next to it to confirm (in my case, they had to rev it pretty high to get it to do it; usually it won't do it sitting still).

I got a good scare the first time it happened, because I was offroading and going downhill in 1st. It totally sounded like it was coming from the transmission. It sounded BAD.

When I was at the exhaust shop last, I had the guy tack-weld the heat shield, where it had started to separate from the exhaust and rattle. It helped, but I still get the noise occasionally.

Knowing what it is, I worry a lot less about it!

 

[kolelt]

Guys, have you checked your exhaust ? Making sure it's not riding on the cross member and that the heat shield isn't falling apart ?

 

[Mr.Rick]

That's what my rattle was, it was a heat shield that rattled but only under the right load. It took me forever to find. It made contact because it was tweaked ever so slightly from a wheeling trip. It only did it under load when the drive train was moving torque at the lower rpms, once the vehicle settled into its normal torque range it was fine.

I had the same issue with a clunk that turned out to be the front drive shaft needing grease. It used to clunk when I was coming to a stop, thought it was a tranny mount... nope just needed some good ole grease in the zerks

these things are reliable as hell but they do have their quirks

 

[kolelt]

That's what my rattle was, it was a heat shield that rattled but only under the right load. It took me forever to find. It made contact because it was tweaked ever so slightly from a wheeling trip. It only did it under load when the drive train was moving torque at the lower rpms, once the vehicle settled into its normal torque range it was fine.

I had the same issue with a clunk that turned out to be the front drive shaft needing grease. It used to clunk when I was coming to a stop, thought it was a tranny mount... nope just needed some good ole grease in the zerks

these things are reliable as hell but they do have their quirks

Don't say , I didn't say to look at that !!!! Ask me how I know ??

 

[Difflock]

I had that issue, while revving or coming off rev and my O2 sensor was falling out,


Sent from my iPhone using Tapatalk

 

[Riceye]

As crazy as it may sound, check your spark plugs to be sure they are all torqued down.

 

[jgue467]

My rattle came at idle in gear only - From around the transfer case. Thought chain got stretched on an I70 climb.

Turned out to be two loose bolts holding the transfer case dampner, they s/b at 28 ft lbs. Luck. :cowboy:

 

[Nottoday]

It was indeed an exhaust leak after all. Thank you every one for your input however!! Very much appreciated!!

 

[Nottoday]

Any updates? Mine is doing the exact same thing. Slight rattly noise only while engine is revving. Usually just before the trans shifts up to the next gear.

My issues was indeed a very small leak. Only when exhaust was warmed up there was a slight gag where the manifolds connect to the down pipe.