xjrunner25

Have a 99 jeep cherokee that I am working on building geared axles for. The axle I am working on right now is an 8.25 out of a 94 (I think) cherokee. I ordered a ring and pinion and rebuild kit from rustys offroad. The problem I have run into is it seems the pinion is the wrong size for the pinion bearing they gave me. And it looks like it's a different size from the original pinion. Anybody ever run into this issue?

JBimmolate

Well if the bearing is the right bearing number (matches the old bearings) and it does not fit the gear then you may have a wrong gearset for that application. The pinion bearing will be a press fit so you will need to press it on with a press. It should not slip on. If you set both pinions side by side they should look almost the same except for the size of the gear head (unless they are the same ratio). If not again wrong application. Do you have any pics of the 2 gears and maybe a pic of your diff? The 8.25 has adjusters for the carrier where the Model 35 has shims to set the backlash.

Miles

xjrunner25

I will have to get a picture of the two but just by looking at them it looks like the new pinion is taller and thicker than the original one. Was there a change in pinion size in the 8.25s at some point in the 90s? It's definitely an 8.25, it has the side adjusters.

Lowrange2

It should be the same size pinion. There wasn't a change. Is there any reason you're downgrading from 29 spline axles to 27 spline?

When you put the geared housing back in the Jeep be sure to use the 29 spline shafts and spiders.

Have you ever geared an axle before?

xjrunner25

Didn't think it would really matter. The jeep only sees some light trail use and is more of a daily driver. I really just want to see if I can get some better mileage out of it and still run 33s. And no I haven't done this before. I'm just kinda learning as I go.

Lowrange2

It won't really make a huge difference but there's no sense in downgrading.

Since you've never done this before, all I can say is take your time, make sure you have all the right tools to do it correctly and read this article and follow it to the T. The article is on gearing a Dana 60 but the same concepts apply.

http://www.billavista.com/Tech/Artic...ble/index.html

There's not reason you can't do it but make sure it's perfect or you'll be doing it again in the near future.

Lowrange2

I'm not sure if 29 spline side gears will fit in the 27 spline carrier but it's worth a shot.

Strmtrooper70

I have the complete spider gears out of a 29 spline one I took em out when I installed my locker if u need em.

94XjSport94

From all the threads i have read on NAXJA, they wont.

Like this: http://www.naxja.org/forum/showthread.php?t=912532

Demonoid369

I'd say look up part number for the carrier, if the 27 and 29 carrier are the same number, then its a matter of swapping spider gears and shafts

94XjSport94

Or, read the link.

sreeb

The axle won't even fit through the carrier hole.

Lowrange2

That's what i figured.

So, he's down grading axles.

I'd sure be gearing the 99 axle...

xjrunner25

I figured I would get another set of axles to re gear then swap them under since it would mean less downtime for the jeep. The axles I got were just the first ones that I found available. I guess I need to do a bit more research next time haha. Like I said before though, the jeep doesn't see a lot of hard trails. Mostly just pines trails. Do you think I'll be alright with the 27 spline?

krazynezz

You'll probably be fine. I've been running a 27 spline welded with 35s for a while. Sounds like I'm gonna lose a bearing soon, but I've got full widths going in soon so I'm not worried about it. But open with 33s I imagine won't be an issue.