NathanJay

Hi all.
First off, I just want to say this is my first post here. I’ve only owned my ’01 XJ for a couple months and I’m brand new to the forum. This will be my first “major” project on the Jeep. Alright, here we go….

I have a bad front differential (Dana 30 low pinion) that needs to be overhauled. I figure if I’m gonna do the front, might as well do the rear right? (Chrysler 8.25). The problem is this is my daily driver so I can’t leisurely pull the axles and take my time with it so I’m going to purchase replacement axles, overhaul them, then swap them out.

I found a Dana 30 high pinion and Chrysler 8.25 pair for sale out of a ’93 XJ. From what I’ve read on the forums this should be a direct swap, correct? My understanding is 1-piece Dana 30 axles were used from ‘92+ and the new reverse gears and my existing driveshaft will work going from low to high pinion. I should be able to use my existing (beefier) axle shafts out of my ’01 both front and rear. Brakes, hubs and all should bolt right on and there should be no issues with perch locations.

From what I’ve read, I should have 3:73 gears stock. ('01 Limited with tow package.) This set up is 3:55. I’m fine switching ratios for now, a speedo gear is $30 online.

I tried to do as much research as I could before posting, I would appreciate a heads up for any potential issues I may have overlooked.

Thanks in advance everyone!

Nate

citRon

you will hate losing the 3.73's...what's wrong with the front diff?

NathanJay

I've thought about that, and am trying to figure out how I can do the swap/overhaul one axle at a time and preserve my current gear ratio. I was thinking about doing the front first, leaving my front driveshaft off, doing the rear, and connecting it all on reassembly.

It was unclear exactly what is wrong, as I brought it to a Jeep dealer and all the detail they gave me was "you need a new front axle". There's definitely something going on, I took it to Jeep more so to verify my suspicion rather than a full diagnosis. To me it feels like I have a major backlash issue, and/or the pinion/carrier bearings are shot. I feel it releasing the break on down-hills, a clunk, and also hear a noise at high speeds when I go between throttle and coasting. Lastly, in reverse there's a grinding sensation that hums the entire cabin.

md21722

97+ 8.25 axles were 29 spline
Earlier 8.25 axles were 27 spline

They do not interchange unless you are swapping carriers

If this is a daily driver, I would swap both axles without interchanging any parts. That way if the new axles have a problem, you can always put the old one back in right away. If you like the new HP D30 then you can always take your time and swap the axle shafts later.

Keep in mind when you swap the front axle you lose your ball joints, bushings that are pressed into the axle, and wheel bearings/hubs, unless you swap those.

NathanJay

That's great info, thanks for that. I'm thinking a full swap will happen like you recommend. It's a DD not an off road monster. (That's gonna be Cherokee #2...)

If I'm tearing it apart I was kind of thinking about replacing it all while I'm in there: hubs, ball/u-joints, even tie rod ends and maybe even rotors, calipers and brake lines. Heck, go big or go home right?

md21722

I'd make sure those new axles work before dropping money on parts for it. If they make noise its a waste of your time to be changing ball joints and stuff like that. Once you know they are good then I'd go do whatever else is needed in the steering or suspension.

IF you don't want to mess with the rear brakes too much and keep yours, you can just take off the entire backing plate with the brakes and brake lines and put it on the donor axle.

NathanJay

How would you recommend checking if the axles are good or not before installing them? I was thinking about overhauling them before swapping them in, so wouldn't that fix any potential problems?

md21722

if rebuilding them means dropping them off at a driveline shop that's going to inspect the ring and pinion and put in all new carrier and pinion bearings then I wouldn't worry about it. Blast away with ball joints etc.

If rebuilding means doing the ball joints and brakes, then I'd wait until you have them installed and confirmed the axles aren't making noise.

You can check for play and roughness particularly in the pinion. Just try to turn it by hand and see if there is any roughness. Should be nice and smooth. If not, get another axle or rebuild.

NathanJay

Ok that's what I thought, I just wanted to make sure there wasn't anything else I should be looking for in the process. I'm going to strip the axles down, possibly get new (stronger) LCA mounts welded on and do a full overhaul.

I ended up pulling the trigger on the axles. The price was right, especially with the D30 high pinion as a bonus.