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Need experienced input. 2000 wj Front Diff.

Old 12-02-2017, 06:21 PM
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Default Need experienced input. 2000 wj Front Diff.

Hello everyone,

New to the forum. After doing some research I stil have a couple questions that I couldn’t seem to find the answer to. I am hot on the trail about to purchase a WJ. I have always done my own work on everything I’ve owned and now I am getting into something i am a little unfamiliar with. Hope you guys with some Jeep experience and solid axles can help me make a decision.

Specs

Asking 1200$ cash

2000
sleet trac 4wd
156k miles
4” lift
adjustable upper and lower c-arms
1” tcase drop
new hubs
Double cardone drive shaft
new kumho 31” tires and American racing wheels
Ball joints recently done
tie rods recently done

comes with stock Jeep wheels with 31” mud tires, some stock parts and spring pacers that he had on for a short period of time.




This Cherokee is mint from what I can see. Guy never wheeled it. It was all show from what I can tell. The lift and front end upgrades all look very recent. Owner had it for last five years and has babied it along with putting a lot of money into upgrades and has been doing all the work himself.

Heres the issue: About 3 weeks ago he was on the highway when there came a bang from underneath and he suspected it was the front diff. So he pulled the new ds and limped home. He said he pulled the cover and couldn’t see any damage. Put clean fluid back on it. He knows he is in above his head. Now he’s selling it for 1200$. I went and looked at it today. Soon as we start rolling I can hear the growling from the diff. It gets louder the faster we go. There is no ds hooked up because he took it out whensomethong went “bang” and hasn’t put it back in. So we parked it back in the yard and upon further inspection I noticed that fluid was already leaking from the yoke on the front diff. When we drove it around the block, I was surprised that 31” tires were rubbing as bad as they were with a 4” lift. He mentioned that he had tinkered with the angle of the ds and “moved” the axle forward by adjusting the control arms. There is maybe 1/16-1/8” of play when I wiggles the yoke. And I also noticed that there was a clicking noise when backing up into his drive way.

Conclusion: everything looks too new for this issue to not be directly related to him installing lift etc, and not getting the pinion angle correct and then he wiped out pinion bearings and probably even the carrier bearings. Without a jack or pulling the cover to the diff I am kind of guessing based on the mechanical skills that I do have being a boat mechanic and doing all my own work over the years. I’ve done a little research and this seems the most logical. I ruled out tcase issues ( stretched chain ).

And I’m pretty sure this is a steal for 1200$ - the lift, two sets of fires and wheels, and all front end upgrades, New is pump and lines, New fan clutch, cold air intake, new brakes, new shot all over the place. I could part it out and double my money I do believe. But I’d rather fix her and drive her for a while. I’ve always wanted one of those. I think the universe is pulling me in this direction. : )



Question: Does anyone have any input before I pull the trigger on this rig and get dirty? This rig is gonna be a winter truck for me and then I’ll flip it in the spring to make my money back and a little extra. Does anyone think it could be something else bigger? And I figure I can do 90% of the job myself but I will bring the carrier down to my friend and have him set the back lash etc.

i couldnt find find a good write up for a rebuild? Anyone have a link?

Thank you all in advance!!!!
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Old 12-04-2017, 10:29 AM
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You may find installing a used complete axle to your advantage. My mechanic found a used rear for mine and had it installed to 8 hours while still handling customers in his shop. The only reason I had him do it was I'm physically challenged and time was a consideration. The best part is I now have a parking brake that works!

The carrier doesn't separate from the axle like a Ford. You'll have to take the entire axle to him. It sounds like the pinion bearings are toast so you'll need a total rebuild anyway.

Last edited by dave1123; 12-04-2017 at 10:34 AM.
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Old 12-05-2017, 07:16 PM
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for 1200 bucks its hard to go wrong, especially if its not your DD
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Old 12-06-2017, 12:16 AM
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So I’m going to pick it up Friday. I’ll be able to get an axle locally for around 250$. I have no problem changing it out and all. What I’m not familiar with is setting pinion angle and adjusting the control arms. As I mentioned in my first post, I suspect that this is how he wipedthis axle out. I don’t want to make the same mistake. Any write ups on setting pinions angle etc.?
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Old 12-06-2017, 01:29 AM
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This model has a front driveshaft with a CV joint at the differential. When lifted, the length must be adjusted to keep the motion within the slip limits of the joint. If it isn't, it may have been pressing on the pinion bearings and overloading them. The best way to fix that is with a driveshaft with a double-carden joint on the t/case end and a single u-joint at the diff. That puts the motion in a longer splined section in the middle of the shaft.

This will require changing the differential yoke for a u-joint type and resetting the pinion bearing preload. Also remember the axle you replace it with must come from a 99-04 because of the change in tread width and wheel bolt pattern.

The pinion angle will be fine as long as the caster angle is set to approximately 7* plus or minus 1/2*.

Last edited by dave1123; 12-06-2017 at 01:34 AM.
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Old 12-06-2017, 05:57 AM
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Originally Posted by dave1123 View Post
This model has a front driveshaft with a CV joint at the differential. When lifted, the length must be adjusted to keep the motion within the slip limits of the joint. If it isn't, it may have been pressing on the pinion bearings and overloading them. The best way to fix that is with a driveshaft with a double-carden joint on the t/case end and a single u-joint at the diff. That puts the motion in a longer splined section in the middle of the shaft.

This will require changing the differential yoke for a u-joint type and resetting the pinion bearing preload. Also remember the axle you replace it with must come from a 99-04 because of the change in tread width and wheel bolt pattern.

The pinion angle will be fine as long as the caster angle is set to approximately 7* plus or minus 1/2*.

Ok. So this leads to exactly what I had suspected. The original drive shaft “ blew “ up on him after the lift was put in. And once he put in the double carden drive shaft. I don’t think it was long after that that the axle blew up. “ resetting pinion bearing preload “ is where I think he went wrong once the new DS was installed. Based on what I know I highly doubt this was ever done. And the original drive shaft blew up because the lift he installed is a 4 “ kit . So, good, this all makes sense now.
Is there anything else I should pay attention to or look out for as I pick this Jeep up and swap in a new axle? I’m sure I’ll have more questions come Friday.
Thanks again
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Old 12-06-2017, 09:38 AM
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I can't tell you HOW many times people get into trouble changing that diff yoke and just installing it with an impact wrench! There is a crush sleeve between the pinion bearings that controls the preload, or running pressure. This is set by using a "torque-to-turn" measurement, I think it's 18 -20 inch-pounds. That's what it is supposed to take to turn just the pinion, but you can get it close with the brake rotors removed and the axle hanging free. In other words, the torque required to just turn the gears. When changing the yoke, or just the pinion seal, this torque must be held closely or the bearings can burn up real quick!

It takes close to 200 foot-pounds to turn the nut! Before you remove it, you have to measure the torque-to-turn the pinion, then match whatever that reading was, plus about 1 inch-pound after you've done whatever operation you did. This requires turning the nut until there's just a little looseness in the bearings, then tightening it just a little more, checking the torque-to-turn in steps until you match the same value. This takes a special wrench (or a huge pipe wrench with a cheater pipe) to hold the yoke and a socket on a long breaker bar to turn the nut. If you're installing new bearings and a new sleeve, It's going to take a lot more torque on the nut to begin crushing that sleeve, but when using the old one, it will come up quickly. Some guys say to mark the nut and pinion with paint and just align the marks, but IDK how effective that is. It's probably okay if you're just replacing the seal. The yoke and flange can be different thicknesses.

There was a long post about a guy regearing a D44 with pictures and step-by-step instructions while he was doing it, but it's old and all the pictures are gone. You might find it with a search, but it was old when I joined in 2010.

The differential is THE most important part of a vehicle, AND the least understood! EVERY vehicle has at least one! With front drive cars, it's inside the transmission.

Last edited by dave1123; 12-06-2017 at 09:58 AM.
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