Excessive road noise. Head explodity.

[Rot Box]

I feel like I've memorized all of the weird noise threads and I still can't seem to figure this one out. Since I bought my 100 a year ago I get this booming/sub woofer sound inside the entire cab and it has proven impossible to figure out where it's coming from. I just wrapped up a trip to Moab and the long drive there and back was completely miserable--I've had enough

The noise: Boom-boomm-boooommmm-boom-booommm. Like when you're sitting next to somebody in traffic who has a loud stereo system except this time you can't figure out where it is coming from. Dirt roads it always there which seems expected. County roads it's there 98% of the time. Freeway noticeable all the time especially at higher speeds. 68mph is the loudest. If I was deaf I would not know there was a problem. NO vibrations, no clanking/rattling/clashing of the drivetrain nothing that I can tell. No amount of braking, throttle, swerving etc can make the sound better or worse. If I speed from 68 to 73 mph it kinda sorta goes away but not much.

What I've tried so far
-pulled rear drive shaft and drove with the center locked up to 75mph.
-pulled the drive flanges and front drive shaft and drove up to 75mph.
-Checked front wheel bearings. Tight. Greased. Feel smooth when turning by hand.
-Checked needle bearing on hub for CV's. Good, tight and greased.
-Checked both drive shafts u-joints. Rear has minuscule amount of play in rearmost joint. So little in fact I'm questioning myself on that one lol.
-New BFG AT 295's. Balanced.
-Steering is tight.
-Ball joints and rod ends feel good.
-inspected all of the body mounts, motor mounts, sway bar links, control arm bushings etc.
-Set the proper rake for the suspension. (My first post here was about this noise and a vibration. Setting the rake cured the vibration--thanks again everyone)

What I have not tried:
-Installing one of those weird rubber things to the undercarriage.... I couldn't tell if people were joking or not when they suggested adding it haha.

Any ideas? The few mods I have are listed in my sig. Thanks,

Andrew

 

[SanDiegoCruiser]

Have you tried placing some hose clamps around you cat shields? I had a similar issue a year ago and this fixed it!

 

[OregonLC]

Front or rear? Engine cover? If you have sliders are they contacting the body pan? Spare loose?

 

[re_guderian]

Pop your rear springs out. Do they have the rubber isolator on top still? Or are you metal on metal?

 

[2001LC]

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What I have not tried:
-Installing one of those weird rubber things to the undercarriage.... I couldn't tell if people were joking or not when they suggested adding it haha.

Andrew

If you mean the "flux capacitor" as it's been called: see Question about attachment to undercarriage.

If all else fails try it, it may still be free from dealer, can't hurt.

 

[Rot Box]

Thanks for the responses everyone I really appreciate the help. The rear bumper was a little loose so I took it off hoping that might have something to do with it. Nope. How far apart should the engine mount separate? I can wedge a pry bar in the middle of it and separate the two halves a little bit.. Kinda doubting that's it.

Have you tried placing some hose clamps around you cat shields?

Haven't tried that. They seem to be in good shape but I'm desperate when I go back to work Monday I'll snag some and give it a shot.

Front or rear? Engine cover? If you have sliders are they contacting the body pan? Spare loose?

I want to say front but it's hard to tell. Took my brother for a ride today and he seems to think it's coming from the front. Engine cover is off, sliders aren't hitting the body (still makes the sound with them removed) and I removed the spare.

Pop your rear springs out. Do they have the rubber isolator on top still? Or are you metal on metal?

It looks to still have them assuming the isolator is attached to the big rubber bump stop.

If all else fails try it, it may still be free from dealer, can't hurt.

That's the one lol. I'll give them a call on Monday.

 

[OregonLC]

I think you may be onto something with the engine mounts. It's been a while since I did my headers but IIRC the mount bolt holds it tight against the hard rubber. Maybe someone who has done mounts recently can help.

Sounds like you're doing all the right things from the standpoint of process of elimination. Boomy, low frequency noise takes substantial mass/energy so keep looking at heavy items.

How about OE jack?

 

[2001LC]

T** How far apart should the engine mount separate? I can wedge a pry bar in the middle of it and separate the two halves a little bit.. Kinda doubting that's it.
***.

Engine mount test: Two person job, put in drive with E brake on and foot brake tightly held while closely watching mounts (use a flood light to see clearly), then repeat in reverse. Any movement and replace. Don't get under path of wheels, too be safe.

"Flux capacitor" no joke, boom sound with-out.

 

[fireball]

I would bet it's that big piece on the PS frame rail. When I removed my running boards I took it off. There was a very noticable booming resonance when driving. Put it back on, no more noise. Installed sliders and now you can't see the ugly piece, problem doubly solved!

That's my n=1 experience.

 

[Sandroad]

Carefully check the exhaust system. Holes, bad hangers, rusted muffler, loose clamps? If OEM, is the anti-resonance device still on the back of the muffler? Are the pipes hitting the body or any other part? Cat shields ok?

 

[re_guderian]

...It looks to still have them assuming the isolator is attached to the big rubber bump stop...

it's not attached to anything, just a floppy rubber washer that sits on top of the coil to prevent metal on metal. Who installed your OME lift?

 

[OregonLC]

I would bet it's that big piece on the PS frame rail. When I removed my running boards I took it off. There was a very noticeable booming resonance when driving. Put it back on, no more noise. Installed sliders and now you can't see the ugly piece, problem doubly solved!

That's my n=1 experience.

It's definitely there for a reason. Toyota spent some $$$ on putting it there to solve a problem they detected. I, however, noticed zero difference with it on/off on my 2000. Would be worth a try.

What about body mounts? I suppose they could develop slop over time too?

 

[Mxndrnks]

There is a tsb on the boom. Might locate that. It has a fix that may help. It was linked in a thread here someplace.

 

[re_guderian]

Isn't the tsb for exhaust booming at idle only?

 

[2001LC]

IIRC your correct ^, but hey he may as-well try if it's missing.

 

[Rot Box]

Even coasting this sound won't go away. I was going to turn the key off and see what happens but that seems too dangerous on a newer vehicle lol. The TSB appears to be just for the exhaust. RPM's and speed don't have much effect which makes me wonder. I'm up for anything at this point though hopefully I can get the damper for a good deal.

I'm starting to talk myself into believing it's coming from the front end. Maybe I'll pull off the sway bar (bushings on frame have seen better days although they are not metal on metal yet) and shocks. More bumps or crappier roads make the noise more noticeable. Definitely not a grinding, metal on metal, squeak, drone, vibration sound etc... Turn the trebble on your stereo off and the bass all the way up--that's it.

I can't say thanks enough you guys are great Wish there was someone close by that is familiar with the sounds a lifted 100 should make.. My wife just says 'uh.. not sure.. well its kind of a humming sound I think' LOL

Carefully check the exhaust system. Holes, bad hangers, rusted muffler, loose clamps? If OEM, is the anti-resonance device still on the back of the muffler? Are the pipes hitting the body or any other part? Cat shields ok?

I replaced the muffler recently. I looked again really close to make sure nothing was leaking or banging around/contacting the body. Everything seems good to go. Anti-resonance is still there as well. Nice you mentioned it I had muffler installed a long time ago on my 79 Hilux and they used a crappy mounts which resulted in a similar noise.

it's not attached to anything, just a floppy rubber washer that sits on top of the coil to prevent metal on metal. Who installed your OME lift?

Ok thanks. I'll have to look into that and see if they are still there. The lift was installed prior to me buying it so it's hard to say without tearing into it. The po seemed very meticulous though.

 

[Rot Box]

At the local Toyota dealer. Looks like I'm not eligible for a free crossmember damper due to year and mileage lol. It's only $259.xx and would be here Thursday if I order it now I think I'll pass on this one haha

 

[2000UZJ]

Is it RPM related? Or does it increase with tire speed? Next time you hear it put it in neutral and coast. Tires can produce a lot of noise that can sound like a locomotive or rumble.

 

[fireball]

Whereabouts in UT are you? If someone nearby has that damper, and I were you, I'd ask to borrow it for a quick test drive. It's only 2 bolts.

I'm no expert and other guys have far more experience than I do with these vehicles, but your original description was exactly what I experienced when I removed mine!!!

Also, pretty sure lots of folks have removed them, so if that does end up being the culprit I'm sure someone will send one your way for a lot less than the dealer cost It should fit into a USPS large flat rate box as well.

P.S. I reserve the right to be 100% incorrect

 

[2001LC]

At the local Toyota dealer. Looks like I'm not eligible for a free crossmember damper due to year and mileage lol. It's only $259.xx and would be here Thursday if I order it now I think I'll pass on this one haha

"Age & mileage" bummer and what a ridiculous price. Try junk yard for frame parts if you come back to this, as possibly affecting your issue.