I've searched around and can't seem to find a definitive answer. I want to reheat my hi pinion dana30 and Chrysler 8.25 to 4.56 so my 94 xj has some decent highway performance and maybe even towing too. What parts do I need? I know on some diffs you needed to get a new carrier to fit those big gears but I don't know if you need it for either of these. What all do I need?
Thanks.

94 xj, 4.0, ax15.

 

Ring and pinion with full rebuild kits for both axles, you will need a new carrier for the front for a 3.73 and up gear set. Also it's good to have 2 extra carrier bearings for the front and an extra inner pinion bearing for both axles so you can make set up bearings out of them. When I did mine I ordered 2 rebuild kits for the front since it was the same price as buying 2 carrier and 1 pinion bearing seperatley. Also you will need to buy or make a tool for the side adjusters on the Chrysler 8.25 axle, and since your 94 8.25 is a 27 spline it would be a good time to upgrade to a 29 spline carrier and axles shafts.

 

Don't forget about the tools.

A good dial indicator on a magnetic base so you can measure backlash, like this one:
A good dial indicating torque wrench, measuring in inch pounds to test bearing preload like this one:
A caliper to measure the shims, like this one:
A good heavy duty torque wrench rated up to 250 lb-ft or so for torquing the pinion nut properly, like this one:
And, of course, a shop press to put the bearings on, like this:
Though you can probably use the cheaper 12 ton press if you wanted to save some money:

 

Thanks!
What's the benefit of going to 29 spline? I don't mind spending the money if I have to but is it necessary? This will be an overland rig primarily and will almost never crawl over rocks if it makes a difference.


Whoa.... Yeah I definitely don't have any of those. Haha thanks

 

Also, I see Dana 30 kits that are for standard or reverse rotation. How do I know which my jeep has? Or are front diffs usually reverse rotation? Does it depend on my transfer case?

 

Front is a high pinion reverse rotation, they switched to a low pinion standard rotation front axle in the 2000 model year.

 

So the rotation is reversed because the pinion gear is on top of the axle as to below on an lp Dana. That makes sense. Thanks!

As far as upgrading to 29 spline? What are the benefits of that? I won't be beating the rig to death at any time so I doubt I'll break the 8.25 if it's a strength thing. Thanks

 

29 spline is stronger, but it sounds like you will be fine with the 27 spline.

 

It may be cheaper to have a shop do the gear install. They will order all the right parts and guarantee the work.

Installing gears isnt rocket surgery but it's precision work that takes some practice to get right. If you don't go through the process of getting the shims just right your gears will eat themselves quickly.

 

Gents, I was doing some googling and I noticed that early jeep liberty models also had Dana 30 fronts (although I couldn't find if they were high or low pinion) and Chrysler 8.25 29 spline rear ends.

Since I'm looking at gears anyway I figured, the 2.4l models had 4.10s in it, and I can rip the 29 spline carrier and gears out of a kj and upgrade my whole back end. AND I'll get rear disks out of the deal too. Thoughts? Cautions?

If this works it would not only save me money because the gears would be cheaper, but I'd also then have a 29 spline rear end so I could actually get the damn trutrac that I want lol.

 

The Liberty's have an ifs front axle, and the rear axle has coil springs so to make it work you have to cut all of the old brackets off, and weld new spring perches and shock mounts on.

 

https://en.wikibooks.org/wiki/Jeep_Liberty/Dana_30a

The front D30 gears are not compatible because of the longer pinion shaft.

And really, you don't want to bother with trying to reuse gears anyway. It's virtually impossible to get them lined up exactly the way they were in the other axle and misalignment of the gears will cause premature wear.

Besides, new gears aren't all that expensive in the context of getting gears installed.

 

What's an ifs front axle?
And the cutting/welding on the rear makes sense.

I guess that makes sense. I guess I was just hoping to be cheap.

Thanks y'all

 

IFS= Independent front suspension.

 

Stronger axle. More importantly is 29 spline opens up options for Limited Slip or locking differentials that 27 spline does not.