Rattle/clatter 1999 3.4v6 2wd

[AntleredRuin]

Ok, so another one of 'those threads'.

I can't tell where it's coming from, but there's a rattle/clatter coming from underneath.
It's driving as normal, except for this LOUD godawful noise.
It sounds 'lightweight', almost. Like its not a clunk, it's a clatter.
There's no pattern to it at all.
Its not 'circular', i.e. not related to wheel rotation.
It's not related to suspension (that I can tell) because it does it on a straightaway and speedbumps or similar don't exacerbate it. I DO need a new UBJ on the drivers side, but if it was that making this commotion I'd suspect I'd have some drivability issues.
It almost sounds like light sheet metal or aluminum foil flapping in the wind and scraping something. My skid plate is completely removed, and the cat converter heat guard is on solid.

It's not the engine, as I can gun it while I park and it's quiet.

Only thing that's changed recently is that I did a TB and WP job about a month ago. Though, like I said, the engine is quiet, so I don't know if that's related.

Maybe I lost a nut/bolt it in the airbox or battery tray or similar and it finally rattled its way loose.

I'll keep looking, but if any of you guys have any ideas, thatd be great so I'm not potentially reinventing the wheel.

Sent from my VS986 using Tapatalk

 

[AntleredRuin]

Maybe a baffle in the cat converter/muffler?
I'm at 186k, but in Texas so virtually 0 rust.

Sent from my VS986 using Tapatalk

 

[Twisted Sid]

Heat shield or cat is coming apart

 

[AntleredRuin]

See, I'd think that too, but wouldn't the cat make noise when simply revving it?
Granted, I haven't laid on my back under it and had my wife sit in the seat and rev, but it was loud enough for me to notice while driving with the windows up.


If it is the cat, any current aftermarket recommendations? I'm NOT going OEM, as there's no way in hell I'm dropping $1k+ for a cat on a vehicle I spent $4300 on. At that price, I'd buy a low mileage junkyard crash with a good cat, take it and anything else I need/want, and part the rest out.
If an aftermarket dies after a few years, I'm willing to buy one again and they often have 5 year warranties anyways.


Any aftermarket part number suggestions? Should I get a 'direct fit' one (with the O2 sensor socket and the piping all the way to the exhaust manifold), or would a good rated universal one (that would fit between the 02 sensors) be enough?

While not ideal, (I know welding is better), I've used those exhaust clamps before successfully for years and have no problem simply clamping a universal one in place after I Sawzall the existing one out if it'll work.

I'm more worried about it throwing a code. Currently, my allegedly broken one isn't throwing a code, it's just loud as hell.

 

[rickmum]

Sway bar bushings might be toast. The sway bar will clang against the frame when the bushing goes.

 

[Kanoe]

See, I'd think that too, but wouldn't the cat make noise when simply revving it?
Granted, I haven't laid on my back under it and had my wife sit in the seat and rev, but it was loud enough for me to notice while driving with the windows up.

Mine has a funny little buzzing that only occurs under load. Rev it all day while sitting and the noise is not there. The engine must vibrate more under load.

Mine is 4 + years in and I have not found it yet, mind you it is not very loud and so I ignore it. I suspect CAT also.

 

[HappyHooligan]

I just fixed a similar noise in mine. Turns out the spring on the front disc brake came loose and just kind of bounced around when I drove. I only heard it with the windows down.

 

[AntleredRuin]

I just fixed a similar noise in mine. Turns out the spring on the front disc brake came loose and just kind of bounced around when I drove. I only heard it with the windows down.

Nah it's not the anti-rattle spring. I have a slight rattle there, but that's because I did the TBU upgrade about a year ago and only installed one spring on each, like stock 4Runner. I hear the TBU likes 2 springs per caliper.

 

[aTALLasian]

Have you checked out your u-joints?

I had a rattle that would turn into a buzz on the highway between 60-70mph and quiet down when I let off the gas. There would also be some major rattling when accelerating from a stop. I replaced my u-joint last night and all the noise has gone away.

 

[AntleredRuin]

Have you checked out your u-joints?

I had a rattle that would turn into a buzz on the highway between 60-70mph and quiet down when I let off the gas. There would also be some major rattling when accelerating from a stop. I replaced my u-joint last night and all the noise has gone away.

Yeah, I actually operated on them just a few weeks ago, and the grease is still good, etc.



I'm all but positive now that it's the cat. I'll grab one from Advance Auto (love their online coupons) and have at it. Worst case scenario is it doesn't fix the issue and I have to return it and reattach my old cat.

 

[AntleredRuin]

Yeah which is what happened. Got the new cat attached, started it up, backed down the driveway, then clang clang clang.
Damnit. Reattached the original cat and my father in law is coming over soon for a 2nd pair of eyes.


Sent from my VS986 using Tapatalk

 

[AntleredRuin]

:redbrick:OK so follow up with a fix, and I really really hate myself for it.

It was the foremost u-joint (closest to the tranny).
My father in law and I took it for a test drive and isolated the noise to the center of the vehicle, so we jacked it up and put it in drive to see. (we used 4 jack stands in the back and chocked the living hell out of the front wheels, don't worry.)

We determined the location the noise was coming from, so he went home and I pulled the driveshaft to check. Oh yeah, the front u-joint was so seized that I could not move it by hand. I finally put some weight into it and got it to move with a loud POP so yeah.

The real pisser about this is that this was a new (to me) driveshaft, complete with greasable u-joints that I had gotten from a junkyard about 4 months ago, and I'd greased them twice since then. I had bought this driveshaft after spending about 11 hours over the Christmas weekend royally ****ing up my original driveshaft yokes trying to remove my original 175k miles seized u-joints. I had broken an impact rated socket, and actually squished the u-joints trying to press them out, and warped the yokes in the process. So like $50 to a nearby junkyard, greased the 'new' u-joints, threw the new driveshaft in, and all was good. Except for not, apparently.

But I digress. Well, the DS was already out, so I just called a nearby mechanic and asked about pricing and then went and dropped the DS off with my wife's car. $150 and one day later, I now have 2 new sealed u-joints with a 3 year warranty and a functional vehicle again.

I'm usually all for doing my own work (just did my TB and WP myself a few weeks ago with no issue), But apparently u-joints are my limit, and that was money well spent, IMO.

So, all in all, I completely wasted about $25 in new clamps and exhaust putty reattaching my original cat after erroneously removing it. I completely wasted probably 6 hours in the whole cat ordeal (trips to Advance Auto, chopping mine out, attaching the new, removing the new, reattaching the original) and now I have a less than perfect exhaust system to show for all my effort. I just hope it passes inspection in a couple months. We'll see.

I'm all for new-age 'feel your emotions and work through them', yada yada yada, but this one I'm just stuffing. If I feel how pissed I am, i'm putting a wrench through my windshield.:redbrick::redbrick::redbrick: