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D30 Cross-Compatibility

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I just pulled a D30 out of a '99XJ w/4.0L, AW4, NP242 and it's bent. I need an axle in it to move it before it gets torn down. The only unused, spare axle I have is still sitting under my '88MJ SporTruck w/4.0L, BA-10/5, NP231. I understand that the axle ratio on my XJ is more than likely 3.55 (haven't checked yet, but can tomorrow) and the ratio on my MJ is 3.07 (also not entirely sure). Either way, I don't intend on using the XJ in 4WD, I just need something to bolt the wheels to and steer it around so I'll just remove the front driveshaft.


My question is are the two axles between the two years completely compatible from a bolt-on and go standpoint? The control arm mounting points all seem to be in the correct locations, but the '88 D30 is a vacuum disco and the passenger upper control arm mount is cast into the axle whereas the XJ mount is piece of sheet metal.


Anyone know? Thanks.

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You have the correct assumption on gearing.


4.0 Auto = 3.55

4.0 Manual = 3.07


Other than that....yes, the 88 D30 can be used as a roller....LEAVE THE DRIVESHAFT OUT.


The actual TUBE is bent?


Front driveshaft has already been removed. This thing will not see 4WD with this loaner D30 in.


Yes, the actual tube is bent. Came out of an XJ I just picked up that was involved in a front end collision. All four control arms bent, control arm mounts on axle bent/snapped, passenger side of the axle pushed back several inches, passenger side axle tube bent.




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D30 tube's bending isn't uncommon.


I can vouch for that. I ended up bending the D30 up front on my old Cherokee while wheeling it. Then when I totaled the Jeep (hit an F350), the accident ripped all the brackets and bent the new axle. :mad:

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