Lesson Learned...

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eekvonzipper

eekvonzipper

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So, I bought this Crappy Project for a Winter Toy/3rd Vehicle. I got it running and attempted a Test-Drive. ('95 Cherokee w/270k miles)
ChittyChitty BangBang ClunkClunk Pop! Rear-End is about to Jump Out of this thing.
So up on Jackstands and have a Look and Listen Running, in Drive. Pop Pop Pop Pop Pop Pop on the Outside of the Axles.
I did Outer Wheel Bearings and Seals. A bunch of water came out when I removed the cover too!
Put it back together and... Same Noise, No Fix. Well, this 8 1/4" Chrysler needs some help. I bought a Full Kit. Ring and Pinion, Bearings, Spiders, All the goodies.
And Needless to say, after all of that work it Still sounds the same.

20250904_191423.jpg


20251019_143829.jpg
This Jeep has had one of the Rough Country 3 1/2" Lifts installed by the P.O. and I guess the Pinion Angle has been the Culprit all along.
(I didn't Think of that) So, now I'll try to Lower it a Bit in the Rear and Shim the Rear Leafs... maybe try to Lower the Transfer-Case some to get the Driveshaft a little more in-line?
It looks pretty bad in the Front.
Any Suggestions?

Output.jpg
 
Get a mechanics stethoscope and locate the point of the sound.

Thought. The rear looks raised might it be the pinion angle to the drive shaft is too extreme?
 
Has Adjustable Leafs too but That wont help because the Hole it was in is the Only one I can use...
The next hole Above and Behind it puts the Shackle in a Bind inside the Mount. (What a Shitty Design, Thanks China!)
Can't even get the Bolt in when trying to use the Upper Row of holes. Genius!

20251116_134402.jpg
 
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This is what the Shaft Looks like from the Pics that I already have (No Full-Length Pics yet)
The Solution is Shims between the Leaf-Pad and the Leaf-Springs on the Back-Side of the pads, Correct?

Upper.jpg


Lower.jpg
 
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I'm not sure yet what a "Slip Yoke Eliminator" is but I Can Move the Rear Forward to close that gap. Spring Perches give some options...

20251116_153836.jpg
but Thinking about it, Wouldn't Shimming the Pinion up and Shimming the Transfer-Case Down put the Shaft back "In" the proper depth?
 
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As far as driveshafts go, you want equal but opposite angles on both sides of the driveshafts to avoid the binding youre noticing. In cars it's ballpark 3* rule of thumb on both sides
That is difficult on 4x4 suspension so typically you want one side to eat up all the angle instead (trans/transfer case side) so you install a double-cardan joint (basically 2 u-joints stacked on top of eachother) on the top to gain that flexibility and you make the axle side about as in line with the driveshaft as you can so that when it flexes up and down it can flex with the driveshaft.
Go to a driveline shop and have them fab up a correct length driveshaft with the correct joint at the top and you should be good. (With the lift kit your stock driveshaft now looks too small)
You can also get a kit to lower your transfer case by about an inch but that is just a band aid IMO and might cause other issues
 

But.... Before throwing anymore money at it. Diagnose exactly where the noise is coming from.

Also if the rear is off the ground have it up in the air with jack stands under the axle tube for the jeep us at relative ride height.
 
@Projectile Dart is on target with this one. According to the off-roaders, the vibration is an inherent problem with more than two inches of lift because the X-Fer case u-joint angle. This demonstration will make the source of vibration fairly obvious. It sounds a lot like the "lope" you are experiencing in your video.
 
had to run a cv joint on my rear drive shaft on my lifted 74 cheero
might be easyer to drop engine/trans down 2"
that angle is way to steep and drive shaft too short for that lift
 
eekvonzipper said:
Okay, but it is Really hard to tell! That noise transfers everywhere, at first I thought it was in the wheel hubs
Click to expand...
With a long dowl up to your ear or a mechanics stethoscope you will be very surprised at what you can hear. You can tell if it's an axle bearing is bad and on which side.

The sound will be distinctly different and louder the closer to the problem you get
 
Dana67Dart said:
With a long dowl up to your ear or a mechanics stethoscope you will be very surprised at what you can hear. You can tell if it's an axle bearing is bad and on which side.

The sound will be distinctly different and louder the closer to the problem you get
Click to expand...
This is a Brand-New Fresh Built Rear... Spins Real nice. But, I'll Spin it again tomorrow and report back.

20251115_144519.jpg
 
eekvonzipper said:
This is a Brand-New Fresh Built Rear... Spins Real nice. But, I'll Spin it again tomorrow and report back
Click to expand...
I don't expect you will find the noise in the diff or bearings, I suspect it will be thru joints / angle. But if there is no sound like you hear but with the stethoscope at the rear of the housing and both ends but it's noticable next to the front of the pinion. You have narrowed it down then listen to the tail housing of the of the transmission.
 
69FBCuda said:
When I lifted my 97 TJ 4 inches I added 1.5" spacer between the frame and trans pan. This lowers the trans output angle.
Click to expand...
Problem with that is it messes up the front drive shaft angle...but at normal driving you wouldn't know
 
nutz said:
Problem with that is it messes up the front drive shaft angle...but at normal driving you wouldn't know
Click to expand...
Did the front axle get rotated to correct the pinion angle. Dropping the xfer case and trans tail putz the drive train at an angle so the engine is tilted back. This should help with the rear driveshaft slip.
 
Just curious, as it’s on the list of things I haven’t worked on yet… how does fan and radiator and other general under hood clearance in an XJ fare when tilting the engine back?
 
Garrett Ellison said:
Just curious, as it’s on the list of things I haven’t worked on yet… how does fan and radiator and other general under hood clearance in an XJ fare when tilting the engine back?
Click to expand...
The motor mounts are the pivot point. So the effect at the front is less drastic. I'm thinking a lever effect(teeter tawter) where the front is 1' and the rear 3', the rear is more drastic than the front.

Watching clearance at the top rear/firewall on the motor. And of course the shifter linkage and shifter will drop more drastically.


Transfer Case Drop Kit | Jeep Cherokee XJ (84-01)/Comanche MJ (86-92)
 
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I think that thing's had a transmission swap at some point to a longer transmission. The drive shaft angle is hideous.
 
Garrett Ellison said:
Just curious, as it’s on the list of things I haven’t worked on yet… how does fan and radiator and other general under hood clearance in an XJ fare when tilting the engine back?
Click to expand...
Think it should have electric fan
That thing has crazy spring mounts
Maybe it needs to come forward an inch too
 
nutz said:
Think it should have electric fan
That thing has crazy spring mounts
Maybe it needs to come forward an inch too
Click to expand...
Has a Clutch Fan on the Passer-Side and an E-Fan on the Drivers-Side.
and Yeah, I'll move it forward if the shimming doesn't bring it in.

engine.jpg
 
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