This sound is driving me NUTS

Joined
Oct 8, 2017
Messages
280
Location
Oneida, TN
Noticed this for a while now. Thought at first it was a rock in my brake shield or something. So I replaced all the rear brakes and components. No dice. I have been all over the underneath of my rig and cannot see anything that would be loose or rattling. To me it sounds like a heat shield, or something....but it seems to be rotational.

Characteristics:
- Noticed only at lower speeds. Most pronounced in parking lots/drive throughs. Still present at higher speeds, but not as pronounced.
- Seems to be more pronounced when coasting, but is also present when driveline is under load. But there seems to be a difference.
- Pretty sure it is in the rear.
- Intermittent - sometimes is really loud and other days, totally silent. Cannot detemine the trigger.
- No feeling of this in steering/braking or anything that corresponds to the sound.
- 1993 FZJ80 on 35s and 3"ish (was on when bought) OME lift.

Here is a video:
End of this video is the best: https://photos.app.goo.gl/W5zyBLYP42AJwR8p9

Notice how it sounds as I am slowing.

Any help is super appreciated!!!!

Scott
 
Joined
Dec 16, 2016
Messages
104
Location
Corvallis OR
What have you worked on recently? When I rebuilt the front end on mine I didn't realize you need to grease the spindles. It made a similar, but slightly more raspy sound, especially when going down hill or turning. It was silent going straight on flat ground or at high speeds.
 
Joined
Oct 8, 2017
Messages
280
Location
Oneida, TN
Interesting. The front end was done just before I bought it, about 9 months ago. I havent touched it since. Did the sound make you think it was in the rear?
 
Joined
Dec 16, 2016
Messages
104
Location
Corvallis OR
From inside the car I couldn't tell which end. With someone else driving I could tell it was the front. It was a similar clank-scrape type noise. At first I thought it must be the dust cover on the back of the brake rotor.
 

HAAANK

SILVER Star
Joined
Nov 25, 2013
Messages
704
Location
Lakewood, Ohio
A couple years ago I had a mystery sound coming from the rear and it ended up being that the view port on the rear caliper was bent up and was scraping against the rim. Passenger side fwiw.
 
Joined
Dec 17, 2007
Messages
3,929
Location
Sydney, Australia
The dust shield on the pinion was my first thought.
Then toasted uni joints in the driveshaft.

Inbollt the shaft, and rotate the uni joint in every direction. It should rotate freely and smoothly through a full range of rotation.
If it's loose, stiff, or not smooth, time for some new OEM uni joints.
It can be hard to judge condition of unis with the shaft bolted in place.

buggered uni joints are typically noisier on deceleration
 
Joined
Oct 8, 2017
Messages
280
Location
Oneida, TN
The dust shield on the pinion was my first thought.
Then toasted uni joints in the driveshaft.

Inbollt the shaft, and rotate the uni joint in every direction. It should rotate freely and smoothly through a full range of rotation.
If it's loose, stiff, or not smooth, time for some new OEM uni joints.
It can be hard to judge condition of unis with the shaft bolted in place.

buggered uni joints are typically noisier on deceleration
Thanks. Could only find Moog joints...are they ok?
 
Joined
Nov 9, 2012
Messages
7,740
Location
Olathe, KS, USA
Moogs are....ok.....
Not as good as the Matsuba / Toyota.

You can run them. The key thing is to make sure they are installed in the CORRECT orientation for the grease zerk location. It needs to be pointed the correct direction (toward the front or rear) based on how the original ones were installed. (Check the FSM) As I understand it, if the zerk is in the wrong place, it COULD break off when rotating due to binding.
 
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