For many of us, it doesn't matter if we've actually broken our stock axles, we know that we probably will. Bigger tires, lockers, and higher-output engines all conspire to wreck stock axles. Often, before we go pouring money into the stock axles, we'll upgrade them whether we need it or not. Here's a list of axles that you may or may not need but make killer swaps into a Jeep.
1. GM Corporate 14-Bolt RearUpside: Cheap, plentiful, and subject of many risqu "shaved" T-shirts. It's a full-floater - it's got a massive ring-and-pinion and gigantic axleshafts.
Downside: Few aftermarket lockers and axles, as well as gearing limitations when compared to the big Dana axles. Also, unless you shave the housing and ring gear, it hangs lower than a Dana 60, and no matter what you do, it's a heavy pig.
Good in: A Jeep that wants a full-width axle and bulletproof strength for cheap. If you aren't afraid of cutting almost 2 inches out of the housing and getting the ring gear diameter turned down, it offers decent clearance.
Avoid: The 14-bolts that don't have full-floating shafts or removable pinion supports.
2. XJ or TJ Rear Dana 44Upside: It's the right width, right bolt pattern, brake lines will bolt in, gets rid of the C-clips, and provides 1.31-inch, 30-spline shafts.
Downside: They are often pricey, the XJ 44 isn't a direct bolt-in for anything but another XJ, nor is the TJ unit a direct bolt-in for anything but a TJ, so some fab work will be required.
Good in: Any Jeep with a 60-inch axle width that just wants to be rid of C-clips and gets the stronger shafts and ring-and-pinion compared to the D35.
Avoid: Paying too much for it if the gears aren't right, brakes aren't good, and it won't bolt into your Jeep.
3. XJ High-PinionDana 30 FrontUpside: Will bolt into TJs and ZJs with no problems. Stronger high-pinion design and correct bolt pattern for most Chrysler Jeeps.
Downside: While your Dana 30 lockers, shafts, and whatnot can be reused, the gears can't be.
Good in: Any YJ, TJ, XJ with a low-pinion or CAD-style housing.
Avoid: The vacuum disconnect units at all costs.
4. Narrow-Track Wagoneer or Early Bronco Dana 44 FrontUpside: Get a real Dana 44 front axle with real hubs and heavier-duty brakes without having to narrow the unit.
Downside: None of your brakes or anything else will swap over. Also, many of the Wagoneer axles have six lugs and will need to be swapped with other Dana 44 front parts for a five-lug pattern.
Good in: Any Jeep looking for an axle with 60-61 inches of width with real Dana 44 (non-Rubicon) issue parts and has no problem outboarding springs or moving spring perches to make it work.
Avoid: If you don't want to narrow the housing, shafts, and incur more costs, stay away from the wide-track Wagoneers and J-Trucks.