So here is the situation, I have a stock '99 XJ that I just replaced the front axle on. Before I replaced the axle everything seemed to run smooth. The steering was tight and other than a shake at around 55. Now I say it "seemed" smooth because the reason I replaced the axle was that where one of the shocks mount to the axle, the mounting bracket was rusted off. That made the suspension bouncy and I don't know if that hid any of the problems.

Now, after the swap, the steering feels loose and there is a juttering that goes on usually above 45, but can happen at lower speeds too. Sometimes it happens when I'm braking and sometimes not. Occasionally it is loud enough to sound like a big rig engine braking (from inside the cab at least). That is not always the case. But overall the shake is not localized to the pedals or steering wheel like it might be with warped rotors. It's more of a generalized vibration that you can hear more than feel if that makes sense.

The new axle is a junkyard axle. I looked at the diff and it looked good. There were no flakes or specks. I moved the passenger side axle shaft from the old assembly to the new assembly because the u-joints were frozen and I couldn't get them out. I kept all the old steering components except the tie rod because the boot of the old tie rod was trashed. I didn't replace any u-joints or ball joints because they didn't look bad either and moved freely. I did replace the steering stabilizer though.
After everything got replaced, I got it aligned and the wheels balanced.

Any ideas on where to look would be appreciated.

 

Was the junkyard axle from an XJ that was in a front end collision?

 

They said it wasn't. But the yard wasn't a pick-a-part type yard so I didn't get to see the donor.

 

If you saved your old axle and if it turns out the new one can't be repaired at a reasonable price you might check out replacement shock/spring perch brackets. Artec, Barnes and Rusty's make these. I used the Barnes product and it worked out terrific. The kit was 150.00. Some welding is required.

 

However, that said, it would seem that most issues would have been discovered and/or corrected during your assembly and the front end alignment. That leaves the bearings in the differential. Did you change the fluid? Anything odd in there?

 

Notice how I avoided saying "Does the differential have fluid?"

 

Haha. That is very nice, quite diplomatic of you.
But I did replace the fluid and I did not notice anything unusual in the old oil. I replaced with a synthetic and everything turned smoothly.

I'm not sure I would be able to reuse the old axle assembly. It's rusted pretty bad all around. However, I could still use the gears because they all look ok.

Is there an easy way to tell if the new axle tubes are bent from a crash, or something else?

 

Start from square one to make sure nothing was overlooked. Jack up the front and have somebody turn the wheel while you observe all the linkage to check out your "steering feels loose" observation. Put some resistance on it while you're doing this. Get a pry bar and make sure the ball joints are good. "Moving freely" is not necessarily a good measure of a ball joint. A new joint is actually a little stiff in its socket. Spin the hubs and really listen. Check the U-joints again. Grab the tire and really put some muscle on it to check for a worn something. Check the condition of the old control arm bushings. Pull the rear driveshaft, engage the 4WD and get the front spinning to recreate the vibration so you can isolate it. If it doesn't vibrate when it's freespinning check the ball joints again. Look where the axle tubes meet the differential to see if the welds are broken. Pull the axles and the carrier and look down the tube to see if its straight. Check for play in the carrier and pinion bearings. Read this from page 3-15 on:

https://cdn.xjjeeps.com/pdf/en-us/19...ice-manual.pdf

Build this:


or use hammer, wrench or rag trick.

 

Before I did that I'd return the axle assembly and demand my money back.

 

Kinda like this?



Trust me when I say, been there, done that:

 

Yeah the mounts are completely rusted, but the differential housing is rusted and flaking as well. Unfortunately I can't weld either so I'm limited in that regard.

My plan it to have it in a shop to get a second look and make sure I didn't miss something. If they can't find anything then I'll have to replace the axle again. Hopefully I'll be able to find one in decent shape if I need to go that route.

 

I'm probably going to have to change my D30 soon because of a bad pinion bearing
and more (again, I did it five years ago, too). I think Dave51 covered most everything,
but here a few questions that come to mind.

Which hubs/rotors do you have on there now? From your old axle or the JY axle?
Do you know at least what year Jeep the JY axle is from?

Did you try using it in 4Hi? How did it perform, any noises?

Did you use a torque wrench to make sure the control arm bushings, track bar, and
tie rods are all tight enough?

 

Any idea how many miles are on the junkyard axle? I've got 265K on my XJ and found pretty bad pitting in the carrier bearings when I pulled it apart chasing a rumbling noise/sensation.

I'm also wondering if they by some chance gave you a low pinion axle instead of a high pinion. That would increase your front driveline angles slightly and could potentially cause vibes if your joints weren't in good shape.

 

I have the cast hub/rotors on there now. And if I remember correctly they said it was a 2000.
I haven't tried it in 4by yet, but I will try this weekend if I can find some time.
I torqued everything to spec in the service manual.

I'm not sure how many miles are on the axle. I didn't look any deeper than a visual inspection with the cover off, but everything looked ok.
If I remember correctly the axle came from a 2000, and I don't think they came with low opinions, correct me if I'm wrong?

 

Some people have always had low opinions of the Dana 30, but those are the same people who hate Fram filters and Bosch O2 sensors.

However, I think it's the other way around. MOST 2000 XJs (and all 2001s) have low pinion D30.

http://www.fourwheeler.com/how-to/tr...ee-axle-guide/