1997 fzj80 noise on decel and at higher speeds

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I'm having a issue with a noise in my 1997 fzj80 that is driving me CRAZY! Please help!! I'll start from the beginning. Bought it about 6 months ago and after a short time developed a noise on decel for a second or 2 but didn't drive it much. Since then did a 3.5 OME lift and the noise began to get worse. Same type of noise even at highway speeds on accel and decel. Thought the noise was coming from the tranfercase and replaced it with a low mileage unit and no change. Next replaced wheel bearings and replaced and lubed spindle bushings and still the same. This weekend replaced all front differential bearings and and no success. Please help!!!!!!!!!!!!!!!!!!!
 

ceylonfj40nut

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Some questions

1) is there vibration or just noise?
2) what does it sound like?
3) does noise change with vehicle speed or constant intensity at any speed?
4) Did you do a caster correction after your lift?
5) check your drive shafts for any looseness
6) Is your transmission mount good?

Attach some pics to show drive shaft angles
 

ToyotaMatt

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I'm having a issue with a noise in my 1997 fzj80 that is driving me CRAZY! Please help!! I'll start from the beginning. Bought it about 6 months ago and after a short time developed a noise on decel for a second or 2 but didn't drive it much. Since then did a 3.5 OME lift and the noise began to get worse. Same type of noise even at highway speeds on accel and decel. Thought the noise was coming from the tranfercase and replaced it with a low mileage unit and no change. Next replaced wheel bearings and replaced and lubed spindle bushings and still the same. This weekend replaced all front differential bearings and and no success. Please help!!!!!!!!!!!!!!!!!!!


all the tech details above you do not describe what the actual noise sounds like at all ?
 

White Sheep

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Very odd noise. Sounds like a bearing. Growling type of noise.
I'm going through the same thing. Been having this for years. People are going to say your u-joints need to be greased or changed. Your pinion angle is off (usually starts when you lift higher than 2.5"). I've changed all this things, and still have the noise. I'm now leaning towards the bearings in my rear differential.

Start with turning your CDL on, remove the rear driveshaft and drive around. If there is no noise, you know its coming from the rear.

Then do the cheaper things mentioned above (u-joints/check your pinion angle) to weed out those as an issue.
 
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ToyotaMatt

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Very odd noise. Sounds like a bearing. Growling type of noise.


it would benefit you greatly before you throw any more parts or $ at this noise ?

- take a simple but very specific cell phone tech video of the noise as you understand it , make note of the noise as it occurs live on your cell phone tech video

i bet you anything , one of the many smart 80 series folks here will be able to pin-point this issuo with oiut a doubt


a photo is worth only 999 words

but a live simple but pin point tech video is worth a million

note : have some one else drive , you focus on shooting the tech video and making notes when it occurs and stops

we don't want u being distracted driver here ...........


this is the way ..........


 
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Is your front DS in phase or out of phase?
Is your rear DS in phase or out of phase?
Which end is your slip yoke? Front and rear
 

Zjohnsonua

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Disconnect the rear driveshaft from the rear diff, and then roll the diff by hand. See if it sounds or feels rough. Sounds like you've replaced nearly all the possible options except for the rear diff bearings, so I'm betting something will be found. Good luck.
 
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Similar happened to me on my old rig, the lift made an unloaded decel growl. It was the front drive shaft. I shook the front shaft and there was really no pIay in it.. finally id'ed it by removing the front shaft and driving around and it eliminated the noise. Put on a tom wood dbl cardan shaft and the rest was history.

That kind of diag only cost me a few beers and some gas to roll around- worth a try.
 

landtank

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At that lift height people usually correct caster which ususlly means a dc front shaft to run smooth. And they also have to adjust the rear pinion angle for the rear shaft to run smooth. Add to that adjustable panhard as front and rear to center the axles.

I’d finish installing the lift which will place sll the geometry back to where it should run clean and move forward with diagnosing any noises from there.
 
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What do you mean by in or out of phase?
The front DS should be 90° out of phase.

The rear should be in phase.

The slip yoke should be towards the FRONT of the truck in BOTH front and rear.

Phase has to do with the orientation of the knuckle on the slip yoke in relation to the knuckle on the fixed end of the DS.

There are a number of threads on here about this and I would find them for you, but I'm on my phone and that doesn't work well for me.
 

Squash

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Pull the rear driveshaft.
Hit the cdl and drive.
If the noise is gone Jon called it first.
Slip yokes allow your d/s to float, if hydro- locked its like a solid steel pipe fighting against the T/C and the up and down motion of your vehicles suspension.
 
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My 96 is doing the same thing, loudest decel noise was front u joints. I still have the rear u joint to change and it will hopefully eliminate the rest of the noise. 2.5" lift in mine when I got it. It also to me goes along with the driveshaft moving in and out.
 
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check for lateral movement in the Uni joints, mine did this a while back (growling / rumbling sound on decel at higher speeds) and i solved it by pressing the bearing cups in a little more on the UNI joint @ rear DS diff end as there was a miniscule amount of movement
 
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Here you go....

 

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