Strange Metallic Scraping Sound?? SOLVED

[Frankiesayrelax]

Original post and symptoms below. The sound was from these kind of metal grating inserts inside of my aftermarket exhaust tips! After some time the came loose and were essentially rattling and spinning slightly causing the metal scraping sound I was hearing. In addition I took to a muffler shop and they added some brackets to my straight piped system (right about where the resonator was).


Hi all any guesses/suggestions/tips/tests appreciated. I’ll attach a video of the sound I uploaded to YouTube.

https://youtube.com/shorts/SJEzuzgGi6U?feature=share

Vehicle in question: 2006 4.4, just over 125k

So I have a strange metallic scraping sound that happens under load (slightly through in N). Presents at low speeds and RPMs (sub 25 mph and 2k RPM), seems to emanate mostly from the passenger side at the front of the vehicle although it is clearly audible form the driver side as well. Doesn’t seem to be a rotational noise (as it does not increase with speed/RPM). My fear is torque converter/transmission/transfer case. I have checked the front suspension. I recently replaced both front axles (should I suspect?). I’ve heard belt noises before and recently replaced the tensioner pulley so I’m doubtful that is the culprit (and again this is a metallic scraping sound). I also recently changed both front and rear diff oils (both were still fairly light for their age and had no evidence of metal shavings, although the front diff didn’t seem to drain out much oil. Suspect?). I do have a slow oil drip at either the oil pan or crankcase covers, but doubt this would contribute? In addition, I haven’t gotten around yet to a decent power steering leak although steering/drivability isn’t affected. Btw, it’s straight piped.

List of things I’ve checked:

- wheel hub/bearing
- rotors + brake pad
- sub frame bushings (control arms, tie rods, sway bar links, track rod ends, etc.)
- guibo is new although I reused the old bolts (I know, I know, supposed to use new)
- CSB seems in good condition and was recently greased up
- just had it aligned

Well, I’m stumped, which is not that hard but still, usually I’m not so any help at all is much appreciated my friends. Cheers.

[andrewwynn]

I'm having a similar strange sound but mine is more Obviously suspension.

It sounds like a suspension creak to me. The revs are torquing motor / xm / suspension bushings.

There is some motion where there shouldn't be.

Try to reproduce with the engine off. Use a long lever like 8' 2x4 and push up on various suspension/ drive train parts.

Check the six bolts that hold the stiffening plate I've heard similar squeaks from similar plates. Check on any heat shields as they are high on suspect list

[Frankiesayrelax]

Originally Posted by andrewwynn

I'm having a similar strange sound but mine is more Obviously suspension.

It sounds like a suspension creak to me. The revs are torquing motor / xm / suspension bushings.

There is some motion where there shouldn't be.

Try to reproduce with the engine off. Use a long lever like 8' 2x4 and push up on various suspension/ drive train parts.

Check the six bolts that hold the stiffening plate I've heard similar squeaks from similar plates. Check on any heat shields as they are high on suspect list

Interesting very interesting, honestly I really disqualified suspension (in my mind) as I’ve crawled around under there enough from all the suspension work I’ve done. I haven’t thought to try moving suspension parts w/ engine off. Will do that.

I forgot to mention that the heat shielding was my first suspect. Although I’m not sure how far it reaches up into the bay. I’ve gone about as far as the cats underneath the car, should I look further up? I also had the stiffening plate off last night (the night before this video) and the sound is the same as before and after I reinstalled the plate. I’ll try levering drivetrain parts as well.

Another note: the engine mounts are new as well.

[andrewwynn]

The impression I get is torque causes it.

It's not likely engine mounts but related. Mounts are softer than new and allowing more movement.

Something that shouldn't touch does. Have somebody else rev engine whilst you poke around

[Emory39]

I would get a plastic mallet and tap the exhaust (specially the cats) sometimes they come apart or break on the middle and the material is stuck and does not goes anywhere. let us know what you find.