Sound that disappears when remove foot from gas pedal (1 Viewer)

[maineidyl]

Started an earlier thread about noise that seems to come from underneath front of vehicle. Sound has become more prevalent. If the metal scraping sound occurs more often now, not affected by speed bumps or road imperfections. When sound starts, (only happens with vehicle moving) if I remove my foot from the gas pedal the noise also disappears. Apply pressure on pedal and sound usually comes right back. Noise is not constant, comes and goes while driving. I have ordered u joints and knuckle kit from Cruiser Outfitters, but not even sure if that is cause. Could a bad muffler make those crazy sounds. Only asking because if I remove foot from the gas pedal the noise stops.
TIA
Tom

 

[maineidyl]

Forgot to mention the vehicle is a 96 LX450 with 190K

 

[Rusty Marlin]

If you run the tires up against a curb and gently apply throttle does the noise appear?
Don't try to jump the curb, but load up the drive train; just to see if it's a heat sheild, or an issue with the enginge/trans assembly moving under load and vibrating on somthing.

 

[maineidyl]

No. Tried at work. Wanted to jump curb but held it back. Since noise is intermittent may have just been sample. Going to try again. Just can’t figure why letting foot off gas affects noise. If I am driving at 30 and let off gas everything is still should be spinning

 

[scottryana]

pinion noise possibly

 

[Njck22]

I had a heat shield rattle that was internmittent. The one along the passenger rocker, definitely check all those out, including exhaust mounts. tap them with a big ole screwdriver and see if it rattles.

 

[katravan]

Tons of info on this:

Drive Shaft PM and Drive Train Troubleshooting- For FAQ​

Drive Shaft PM and Drive Train Troubleshooting- For FAQ

This a compilation of information from Forum members. Driveline issues and troubleshooting can get very complicated and this is by no means a complete and encompassing thread. If you see errors or have key additions, please PM one of the moderators. There are a lot of potential causes to...

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list of sites/links​

Upgraded suspension components: Data points

Hey all: While what I did might be old hat to the experienced heads here, I just wanted to write up a few words about some work I did recently on the rig. First off, I want to say thanks to Christo and Ben and the rest of the folks at Slee. These guys know their stuff and they are an...

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I'm chasing a similar issue myself (noise above 30+ mph that doesn't change in pitch, can be felt through gas pedal & floor under load, goes away when letting foot of gas or going to neutral). Replaced u-joints which didn't look/feel great anyway but issue persisted. Knuckles are next which I don't think is the primary root cause but I gotta get it done.

I've been told it's likely due for a new ring/pinion - in my todo is hook up a microphone underneath.

 

[maineidyl]

Would pinion be intermittent noise?

 

[LandLocked93]

There's always the drive shaft removal routine.
Lock the center diff and remove one drive shaft. Test drive for noise.
Then replace that shaft, and remove the other shaft. Test drive for noise.
When I was hunting on-throttle/lift-throttle noises, this helped narrow it down to the drive shafts themselves.
They weren't bad. They were reinstalled by a shop incorrectly after I had some work done.
You didn't mention anything like that, so it probably isn't your shafts.
But if you don't know when the last time the yokes were greased, wouldn't hurt to slide under there and give'em a few pumps for s&g's.

 

[LINUS]

Would pinion be intermittent noise?

Could be - norm the RR is what whines / then quiet off-throttle, but I wouldn’t rule out a FR.

Is it a whine, a rattle, or a felt & heard vibration under throttle?

-A sound clip might save ~2pgs of guessing……..

 

[ChaseTruck]

Dry/damaged driveline u-joints - give them fresh grease and take it for a spin...?

Sounds too simple, but we went through just that on the GX. Rumble sounds on freeway, can feel a vibe when touching the T-case shifter; both my wife and I think driveline. This is a street car, I try not to work on these, off to Lexus; my wife tells them about a potential driveline issue. Lexus comes back with 'new tires needed' - we didn't think those were an issue, but we have more road trips planned, so we agree. Rumble doesn't go away. Drive by the Landcruiser Spa in Mesa, and it takes Travis like 30 seconds to find a completely dry front driveline u-joint. Not just no grease, in fact, no needle bearings as well. I guess the Lexus electronic diagnostics tree doesn't capture pure mechanical issue...

 

[maineidyl]

Bought a new oem drive shaft for the rear. Came with new joints and balanced. Cheaper for me to pull and replace than to have a local shop pull, replace u joints, balance and reinstall. Cost $367. Problem solved. Cruiser is tighter than new. Would love to download sound clip so others could hear what mine was doing. No idea how. Thanks again. Problem solved.
Tom

 

[cjoez13]

Bought a new oem drive shaft for the rear. Came with new joints and balanced. Cheaper for me to pull and replace than to have a local shop pull, replace u joints, balance and reinstall. Cost $367. Problem solved. Cruiser is tighter than new. Would love to download sound clip so others could hear what mine was doing. No idea how. Thanks again. Problem solved.
Tom

Mind lending your ear? I have a similar noise potentially, does it sound like yours?



Haven't been able to pull the DS..

 

[maineidyl]

Mine was more of a hollow metal spinning sound that stopped when I took foot off of the gas pedal.

 

[LandLocked93]

Mine was more of a hollow metal spinning sound that stopped when I took foot off of the gas pedal.

Did it sound like a metal baseball bat fight between two skilled swordsmen?

 

[LINUS]

Mine was more of a hollow metal spinning sound that stopped when I took foot off of the gas pedal.

That screams pinion slop IMO, from your word-age.