Bugout4x4

I see very very few efforts to swap out to Ford 9 inch rear differentials. Can someone share why there is very little discussion about this option? They are not a C clip diff, they are one of the strongest, all the optional ratios can be had, limited slip carriers are everywhere for these, and they produced axles in both spline counts with the 5 on 4.5 bolt pattern. So why not?

Joshua White

I'd imagine it comes down to the work needed for a fullsize axle to fit properly. If you have to go through all that work you might as well grab what's more readily available? Or perhaps stronger for an intended purpose.

Having never needed that much beef all of this is pure speculation on my part. The guys over at BleepinJeep on the YouTubes did a nine inch build for an XJ and it was pretty popular.

Bugout4x4

I'll have to do some measuring but they made two different housing widths and axle lengths in both spline counts in both the "Big" bearing and "small" bearing sizes. One of the two has got to be real close to these. And all the guts are interchangeable between them all. From all the abuse I have seen these take over the years I can testify they are pretty much bulletproof. So I had to wonder why more haven't done it.

Tbone289

I have a small bearing 9 on my early Bronco, which is one of the narrower ones, but has the wrong bolt circle (5x5.5). See here for the details : http://www.mustangsandmore.com/ubb/F...imensions.html

Bugout4x4

I'm familiar with the bolt patterns, They actually had three different bolt patterns with the smallest being 5x4.5 like the jeep. For a while they had a chevy sized 5x5.75 pattern on the station wagons, T birds, LTDs, and some larger Mercurys. And they made two different width housings and two different spline counts and axle lengths in all three bolt patterns. And the internals were mix and match exchangeable in the three different wheel patterns. I'm pretty sure one can be pieced together to fit the XJ application. (except for spring perches of course, which would have to be fitted and welded)

Tbone289

According to that link there were more than 2 widths of housings. In don't know much about them except for the Bronco--just going by what I read there.

Bugout4x4

Actually I think you are right. I think over the years they did use three different width housings. Have you measured yours against the jeep? I have a 58 f150 here I was about to go measure against the Jeep. Waiting for my "other end of the tape holder" to get back. lol

Tbone289

Other site states that it came in 7(!) housing widths: https://pitstopusa.com/p-4125-ford-9...formation.html

I believe the 8.25 is 60" flange-to-flange, and the 9" in the Bronco is 58".

Bugout4x4

Holy cow! I really did not realize there were so many different housings! And I have been a Ford man all my life! lol

See, now I could live with 1 inch a side difference. I have a later model T bird rear axle here I will measure also. I think they are a little wider than the trucks believe it or not. Because they were a low and wide four link coil set up.

4.3L XJ

Yes, there were many different widths over the years depending on year and model. It was gradually replaced with the 8.8. Also as stated above, there were two different size of axle bearings. The small bearing can fail under hard use or towing (had this happen twice). But that is no different than knowing which 8.25 Jeep axle to use. They are a good rear end and if you want to go full width go well with the Dana 44 front from a pick up or bronco.

Tbone289

Me too. My father has sold Fords for 59 years. He's still in the business at 80. The XJ is the only non-Ford I've ever owned, but I love it.

IIRC, the truck/Bronco housings are thicker than the others, but it's not going to matter much under a 3.3K LB XJ.

Bugout4x4

I have owned a lot of other makes over the years, but they were all pre-80's. Never owned another make made after the 70's. JUNK. lol

I have a full spooled Bronco II sitting out back as we speak. The engine is about done in it from hard wheeling for years. So... I have a Nissan Diesel to drop in it after I first get the Jeep back up and going hopefully soon. But even though the Bronco II will go where this jeep could never think of going, I like that the Jeep is long enough to sleep in. lol

89eliminator

lots of people run a 44/9 combo. thats what i run.

Bugout4x4

Fantastic! Do you mind sharing what housing application and axle application you went with? And what dimension differences are there to the XJ?

Here's the deal... I have a corporate that is wore out and have access to all the 9 inch take outs I could ever need. I could spend the same on this Corporate and a lunch box or fab a 9 inch limited slip in it and spend less to gear it 3.55 to match the front. And the 9" is unbreakable as you know...

Any wisdom and experience you could spare with this swap option would be fantastic man!

Bugout4x4

I would like to pursue this some more.... ?