KJ 8.25"

[casm]

With various other parts on order, I'm doing some forward planning on a rear axle swap to (eventually) get rid of the D35 in my 2000 Limited. Key to this swap has been retaining ABS; I like it for on-road use and want to keep it. The problem is finding an axle that'll retain ABS compatibility with a minimum of fuss and bother.

A KJ 8.25" seems like a good bet - stronger than the D35, has the ABS tone rings in place, and would also yield disc brakes. However, I'm wondering about a few things:

1) How does the KJ 8.25" stack up against the XJ 8.25" dimensionally, both externally and internally? Are the axle shafts similar diameters, etc.?

2) Are the KJ tone rings directly compatible with the XJ ones in terms of inner diameter and count, or would this still require a swap?

If anyone can provide some insight into this, it'd be much appreciated.

 

[CMNCHE]

Shafts are 29 spline. Same ABS manufacturer as XJ so tone rings may be the same. Don't know about dimensions, will measure one tommorow at work.

 

[casm]

Shafts are 29 spline. Same ABS manufacturer as XJ so tone rings may be the same.

Interesting... This is looking more and more like a possible route.

Don't know about dimensions, will measure one tommorow at work.

Thanks - that would be great!

 

[CMNCHE]

The KJ 8.25 is 55.5" from backing plate to backing plate. I will measure my XJ 8.25 this afternoon.

 

[FitchVA]

don't forget that the kj's are not leaf sprung.

 

[casm]

don't forget that the kj's are not leaf sprung.

Yep. Spring perches are part of the plan, but a coilover's not ruled out at this point either.

 

[Grifter144]

damit.. i just walked past a kj 8.25 with the discs at the yard the other day..wish i would have known it was 29 spline..would make for an easy swap for the xj 8.25 to get me discs..unless of course i can strip the discs off that 8.25 at the yard and mount em on my xj 8.25..wonder if that is possible...hmmmm

 

[egon]

Same ABS manufacturer as XJ so tone rings may be the same.

KJs use the tone ring on the ring gear with 1 sensor in the center section. A bit of electrical hackery would be needed to make it work.

--Matt

 

[CMNCHE]

After further research as stated above the sensor is on top of the diff and there is only the one. You may be able to hack this into your XJs current system. There are a crapload of brackets on the KJ axle that would need to be cut off unless you are going spring over. My XJ rear axle measures just a little wider than the KJ axle, but its harder to get a measurment on the KJ because of the aforementioned brackets. They are very close so I doubt the difference would be a problem. Other than a lot of hacking if you stay leaf sprung and figuring out if the sensor would work it looks like a good swap. I will try to get some info on how the ABS is wired and controled in the Libby this afternoon.

 

[casm]

After further research as stated above the sensor is on top of the diff and there is only the one. You may be able to hack this into your XJs current system.

Hm. OK, that's definitely food for thought. Unfortunately the only KJ I have regular access to is non-ABSed, so can't do a direct comparison, but I'll see what I can dig up.

There are a crapload of brackets on the KJ axle that would need to be cut off unless you are going spring over.

Does this apply to the ABS as well as the non-ABS axles? Been awhile since I checked, but the non-ABS units seemed fairly close to the XJ units apart from obvious differences.

My XJ rear axle measures just a little wider than the KJ axle, but its harder to get a measurment on the KJ because of the aforementioned brackets.

No worries. At a rough guess, how much wider are we talking for the XJ axles? Eyeballing them they looked pretty close.

Other than a lot of hacking if you stay leaf sprung and figuring out if the sensor would work it looks like a good swap. I will try to get some info on how the ABS is wired and controled in the Libby this afternoon.

Cool, thanks. Like I said, I'm on the fence about going coil-sprung, but generally prefer it so if it actually facilitates going to a 4-link that's OK in my book.

Also, major thanks for taking the time to look into this - there are zero KJs in the yards around here, so your effort is really appreciated.