Help needed! Mystery grinding noise

[BrettErik13]

I'll appreciate any help I can get on this one. About 3 weeks ago I started hearing a grinding noise from under the front end of my '90 4runner. The noise would start after hitting a bump and generally just last for a few seconds (you can usually feel a vibration through the floor as well).

The noise remained sporadic for the next few days but began to increase in frequency. I had it looked at by a mechanic (I was out of town), who stated he'd never heard anything like this noise before.. put my car up on a lift and said that everything in my front suspension seemed to check out fine (minus a torn cv boot on the r. side). His only thought was that it could be the front differential. Ok.. so here's the weird part.. after he took it off the lift the noise totally disappeared for several days before returning again. He stated he didn't change anything.

Alright.. so I got it back to town and my mechanic check it out. He replaced the r. axle/cv joint, repacked the wheel bearings on both sides, and put on new rotors. Same as before.. the noise disappeared completely for several days after being put on the lift.

I brought it back in again.. this time we replaced worn out bushings on the sway bar. ... and to my dismay.. the noise is still there. So far none of the mechanics have been able to replicate the noise on a lift.

This is wearing down my mind and wallet.

Here's some random other tidbits..

-The noise occurs in both 4wd and 2wd.
-Speed is not a factor.
-Turning the wheel doesn't alter the noise.
-Hitting the gas/break doesn't alter the noise.
-The noise may be worse with colder weather (and started on a very cold day)
-The noise definitely is tied into hitting bumps
-Sometimes the noise seems to be under the front left side of the vehicle, sometimes under the front right side.

Any thoughts?? I've got new bilstein shocks. Does this sound like a bushing issue? Control arm? U-joint? Transfer case?

I'd greatly appreciate any insight on this one.. I haven't found anything really concrete in any of the other posts.

 

[BrettErik13]

Mystery Grinding Noise! Help!

I'll appreciate any help I can get on this one. About 3 weeks ago I started hearing a grinding noise from under the front end of my '90 4runner. The noise would start after hitting a bump and generally just last for a few seconds (you can usually feel a vibration through the floor as well).

The noise remained sporadic for the next few days but began to increase in frequency. I had it looked at by a mechanic (I was out of town), who stated he'd never heard anything like this noise before.. put my car up on a lift and said that everything in my front suspension seemed to check out fine (minus a torn cv boot on the r. side). His only thought was that it could be the front differential. Ok.. so here's the weird part.. after he took it off the lift the noise totally disappeared for several days before returning again. He stated he didn't change anything.

Alright.. so I got it back to town and my mechanic check it out. He replaced the r. axle/cv joint, repacked the wheel bearings on both sides, and put on new rotors. Same as before.. the noise disappeared completely for several days after being put on the lift.

I brought it back in again.. this time we replaced worn out bushings on the sway bar. ... and to my dismay.. the noise is still there. So far none of the mechanics have been able to replicate the noise on a lift.

This is wearing down my mind and wallet.

Here's some random other tidbits..

-The noise occurs in both 4wd and 2wd.
-Speed is not a factor.
-Turning the wheel doesn't alter the noise.
-Hitting the gas/break doesn't alter the noise.
-The noise may be worse with colder weather (and started on a very cold day)
-The noise definitely is tied into hitting bumps
-Sometimes the noise seems to be under the front left side of the vehicle, sometimes under the front right side.

Any thoughts?? I've got new bilstein shocks. Does this sound like a bushing issue? Control arm? U-joint? Transfer case?

I'd greatly appreciate any insight on this one.. I haven't found anything really concrete in any of the other posts.

 

[BrettErik13]

Mystery Grinding Noise! Help!

I'll appreciate any help I can get on this one. About 3 weeks ago I started hearing a grinding noise from under the front end of my '90 4runner. The noise would start after hitting a bump and generally just last for a few seconds (you can usually feel a vibration through the floor as well).

The noise remained sporadic for the next few days but began to increase in frequency. I had it looked at by a mechanic (I was out of town), who stated he'd never heard anything like this noise before.. put my car up on a lift and said that everything in my front suspension seemed to check out fine (minus a torn cv boot on the r. side). His only thought was that it could be the front differential. Ok.. so here's the weird part.. after he took it off the lift the noise totally disappeared for several days before returning again. He stated he didn't change anything.

Alright.. so I got it back to town and my mechanic check it out. He replaced the r. axle/cv joint, repacked the wheel bearings on both sides, and put on new rotors. Same as before.. the noise disappeared completely for several days after being put on the lift.

I brought it back in again.. this time we replaced worn out bushings on the sway bar. ... and to my dismay.. the noise is still there. So far none of the mechanics have been able to replicate the noise on a lift.

This is wearing down my mind and wallet.

Here's some random other tidbits..

-The noise occurs in both 4wd and 2wd.
-Speed is not a factor.
-Turning the wheel doesn't alter the noise.
-Hitting the gas/break doesn't alter the noise.
-The noise may be worse with colder weather (and started on a very cold day)
-The noise definitely is tied into hitting bumps
-Sometimes the noise seems to be under the front left side of the vehicle, sometimes under the front right side.

Any thoughts?? I've got new bilstein shocks. Does this sound like a bushing issue? Control arm? U-joint? Transfer case?

I'd greatly appreciate any insight on this one.. I haven't found anything really concrete in any of the other posts.

 

[BrettErik13]

Mystery Grinding Noise! Help!

I'll appreciate any help I can get on this one. About 3 weeks ago I started hearing a grinding noise from under the front end of my '90 4runner. The noise would start after hitting a bump and generally just last for a few seconds (you can usually feel a vibration through the floor as well).

The noise remained sporadic for the next few days but began to increase in frequency. I had it looked at by a mechanic (I was out of town), who stated he'd never heard anything like this noise before.. put my car up on a lift and said that everything in my front suspension seemed to check out fine (minus a torn cv boot on the r. side). His only thought was that it could be the front differential. Ok.. so here's the weird part.. after he took it off the lift the noise totally disappeared for several days before returning again. He stated he didn't change anything.

Alright.. so I got it back to town and my mechanic check it out. He replaced the r. axle/cv joint, repacked the wheel bearings on both sides, and put on new rotors. Same as before.. the noise disappeared completely for several days after being put on the lift.

I brought it back in again.. this time we replaced worn out bushings on the sway bar. ... and to my dismay.. the noise is still there. So far none of the mechanics have been able to replicate the noise on a lift.

This is wearing down my mind and wallet.

Here's some random other tidbits..

-The noise occurs in both 4wd and 2wd.
-Speed is not a factor.
-Turning the wheel doesn't alter the noise.
-Hitting the gas/break doesn't alter the noise.
-The noise may be worse with colder weather (and started on a very cold day)
-The noise definitely is tied into hitting bumps
-Sometimes the noise seems to be under the front left side of the vehicle, sometimes under the front right side.

Any thoughts?? I've got new bilstein shocks. Does this sound like a bushing issue? Control arm? U-joint? Transfer case?

I'd greatly appreciate any insight on this one.. I haven't found anything really concrete in any of the other posts.

 

[WildMountainBoy]

I have the same problem on my 91 4R, I am stumped also, this happened a few years ago and I ignored it untill my rear Diff. shred to peices driveing home from work I had a slow drip at the plug. I replaced the Diff. wheel bearings, and u-joint and did'nt hear the sound for a year or so, but its back and i have inspected the Diff. but the gear oil seems fine.

Yours may be the rear Diff. especialy since it goes from R to L sides, its strange how noise can travel.

My noise is only on the front passenger side and is speratic at 55+mph and in 4wd, but constant at low speeds and is defanitally worse on cold days. if i make a sharp left turn it stops grinding and is kind of a popping. when i hit a bump it stops briefly. but initally only started when i hit a bump. Im stumped if you figure some thing out please let me know, and i will extend the same curtacy.

 

[Jlobx]

Hey there.
New to the forum. Can't figure out how to post a new thread, picked the closest one to my problem.
It's a very specific grind. Kinda high pitched I'm fearing transmission noise.. happens between 1400 and 1600 RPM, in at least 1st and 2nd gear. Can't determine on other gears because I'm moving too fast to hear the echo off objects.. any ideas????

 

[MFreund]

Hey there.
New to the forum. Can't figure out how to post a new thread, picked the closest one to my problem.
It's a very specific grind. Kinda high pitched I'm fearing transmission noise.. happens between 1400 and 1600 RPM, in at least 1st and 2nd gear. Can't determine on other gears because I'm moving too fast to hear the echo off objects.. any ideas????

Welcome!

You cannot start a thread until you have 15 posts. Mods are trying to keep the spam out.

On a side note.....Doing a great job guys!