What’s Best And The Rest
The Cherokee ran for a whopping 18 years of production, and during that time there were many different axles that the factory bolted to the Unitbody. Most of the time the axles in stock form were actually pretty decent for up to a 35-inch tire. Fortunately, if your XJ didn’t come with the better axles under it, you can often find a good one under an XJ at a junkyard near you thanks to the prevalence of these things in bone yards.
Before you go tossing money at the axles under your Jeep, let’s figure out if they are worth keeping or if you should swap assemblies and put the money into something that will work better for you down the road.
There was just one front axle used for the 18 years of production, but there were three major differences between them and countless minor ones throughout the years.
Dana 30 CAD
The CAD (Center Axle Disconnect) was Detroit’s answer to the public’s desire to be able to “shift-on-the-fly.” Coming into the ’80s, in order to put your 4WD vehicle into 4WD you had to get out and lock the hubs. Normally, we have no problems with that, but in snow, rain, ice, or mud it isn’t the most convenient thing. So, these axles got a vacuum-actuated shift fork and a two-piece long-side axleshaft. In 2WD the long-side shaft wasn’t connected to the drivetrain, which reduced wear and tear of the front driveline. In 4WD, the fork slides a collar over the shaft and voila—4WD without ever leaving the driver’s seat.
This is the least desirable axle of them all. The long-side tube doesn’t go through the cast CAD section and so is prone to breaking if abused. Also, if you lose either vacuum or 12 Volts to the shift fork, you have no 4WD. The U-joints are smaller than ’96-and-later models, and some of the earliest axles used bolt-on caliper mounts.
Good swap options are the later high-pinion Dana 30s from either later XJs or ZJs, or TJ Rubicon front Dana 44s.
Less front driveline wear
Common ring, pinion, and carrier options
Break-prone cast CAD housing
Balky air over electric shifter mechanism
Dana 30 High-Pinion
In the ’80s only the NP242-equipped XJs were getting the non-CAD Dana 30 front axle, but by the time metal was losing popularity to grunge all Cherokees started seeing use of this axle. While theoretically having less stuff spinning up front made for better fuel economy, by the time the XJ got the multiport fuel injection it was much easier to meet CAFE standards and the added cost and complexity of the CAD system was deemed too much.
These axles ran all the way up to ’00, with the ’96-up units enjoying the bigger 760X U-joints that were previously a Dana 44-only joint. Some of the earlier full-time 4WD models used CJ-style joints instead of the later U-joints and are generally regarded as not being as strong. You can swap later 760X-equipped shafts into your earlier Dana 30, but you need to pay attention to unitbearing/rotor/caliper clearances. There was a ¼-inch change in the unitbearing flange-to-flange depth that can cause interference issues between the rotor, caliper, and even the face of the knuckle. It is typically safer to just take all the parts from the donor, however we have had luck mixing and matching parts.
Good swaps are the complete TJ Rubicon Dana 44 or any of the many available aftermarket bolt-in axle assemblies.
One-piece long-side shaft
High-pinion more durable in the front application than low-pinion
Easier to truss than CAD version
Front driveline is always spinning which can lead to premature wear or vibrations
Pre-’96 U-joints break easier
Limited availability of factory-equipped 760X-equipped models
Dana 30 Low-Pinion
The low-pinion Dana 30 showed up in the last couple of years of XJ production (mid ’00 and ’01). The commonly held belief is that Jeep had used up all of the high-pinion housings and assemblies and with the knowledge that the XJ was coming to the end of its life cycle, Jeep just pulled the low-pinion assemblies from the TJ parts bin and tossed them under the Cherokee. The XJ, TJ, and ZJ all share front suspension components, so this was a no-brainer for Jeep.
The low-pinion isn’t as beefy in the front application due to the pinion driving against the coast side of the ring gear teeth. This can lead to easier ring or pinion tooth breakage when compared to its high-pinion counterpart. However, all of these last axles got the larger U-joints for increased overall axleshaft strength.
Good swaps are the ’95-’99 high-pinion housing, the TJ front Dana 44, or any of the many aftermarket options.
No U-joint guessing
Newer assembly generally means less wear if swapping a used one in
Can use hand-me down parts from many TJ guys
Slightly weaker ring and pinion combo
Less driveshaft ground clearance
Less commonly found in junkyards