• JP Magazine
  • Dirt Sports + Off-Road
  • 4-Wheel & Off-Road
  • Four Wheeler

Our Favorite Jeep Axle Swaps

Posted in How To: Transmission Drivetrain on September 1, 2011 Comment (0)
Share this
Our Favorite Jeep Axle Swaps

If you’ve got a Jeep, then you’ve probably come to realize that factory axles are an exercise in mediocrity. Once the vehicle is even slightly modified, their strength always seems to be one step behind the demands of the Jeep’s newfound capability. Snap, pop, and bend is often the result.

Sure, you can upgrade what Toledo gave you to work with. But in many cases it’s better to forget the factory axles and head straight for better options. Usually, a little time spent searching and setting up a stronger set of axles not originally offered in your Jeep model will pay big dividends down the road in terms of strength, survivability, and sanity. So with that said, and in no particular order, here are some of our go-to axles when our trail needs write a check our factory axles can’t cash.

Rockwell 2.5-ton Front/Rear

Found in: Military M35A2 2.5-ton 6x6 trucks
Width between wheel mount surfaces: 79½ inches (hubs out) or 69¼ inches (hubs flipped)
Shaft diameter/spline: 1.62-inch, 16-spline
Common gearing: 6.72
Bolt pattern: 6-on-8 3/4

Pros: They’re strong and inexpensive to buy when compared with 1-ton Dana axles. The double-reduction style centersection can be flipped with a little work to help in drivetrain clearance. Aftermarket steering arms and pinion brake components can be bought or fabricated relatively cheap. They’ll stand up to a good deal of abuse with tires up to 45-inches.

Cons: The shafts aren’t metallurically as strong as modern offerings, so 46-inch and larger tires can take their toll. Additionally, the 6.72 gearing and huge physical size favors at least a 42-inch tire and creative fitment to clear engine and drivetrain. In addition to the small tire size window, the bolt pattern will really limit wheel selection. Once you get into aftermarket shafts and at-the-wheel disc brakes things get expensive. Rockwells are best run in stock (or near-stock) form or not at all, but if you’re running high-horsepower and big meats you’ll have to have really deep pockets to keep your Rockwells alive.

Full-Size Dana 44 (GM/Dodge)

Found in: ’73-’77 Chevy ½- and ¾-ton pickup, Blazer, Suburban; ’80-’84 Dodge ½- and ¾-ton pickup and Ramcharger
Width between wheel mount surfaces: 69 inches (Chevy); 67 inches (Dodge)
Shaft diameter/spline: 1.31-inch, 30-spline
Common gearing: 3.23, 3.54, 3.73, 4.09, 4.56
Bolt pattern: 5-on-5½ (Dodge ½-ton); 6-on 5½ (Chevy ½-ton); 8-on-6½ (Chevy/Dodge ¾-ton)

Pros: They’re still easy to find in junkyards and have one of the strongest aftermarket support systems in place. All Dodge and some Chevy versions have flat-top knuckles for conversion to crossover steering in spring-over applications. Dodge ¾-ton housings have shorter distance between ball joints, so swapping to ½-ton knuckles allows long-side to be shortened for narrower WMS measurement and still work in early Jeep without outboarding springs. Chevy versions can be swapped to 5-on-5½ Ford hubs/rotors easily. Almost all ¾-ton versions came with 4.09 or 4.56 gears.

Cons: Most don’t want to shorten long-side tube and/or outboard springs for use in CJs and YJs. Dodge knuckle versions are unique with few interchangeable parts between other brands or even between ½- or ¾-ton Dodge axles. To go from ½- to ¾-ton you must swap whole knuckle.

FSJ Dana 44

Found in: ’74-’91 Wagoneer, Cherokee, Cherokee Chief, J-truck
Width between wheel mount surfaces: 59½ inches (narrow-track Wagoneer/Cherokee S front); 58½ inches (narrow-track Wagoneer/Cherokee S rear); 66 inches (wide-track Cherokee Chief/J-truck front); 65 inches (wide-track Cherokee Chief/J-truck rear)
Shaft diameter/spline: 1.31-inch, 30-spline
Common gearing: 3.23, 3.54, 4.09
Bolt pattern: 6-on-5½ or 8-on-6½ (some ¾-ton J-trucks)

Pros: The Quadra-Track FSJs have Dana 44 rear axles offset to the passenger-side, which makes use in early Spicer 18-equipped Jeeps nice. The width is more manageable in most CJ and Universal vehicles, and when used with a spring-under front suspension the stock steering can be adapted with little trouble.

Cons: The 6x5½ bolt pattern is only easily converted to 5x5½ on the ’74-’76 small-bearing spindle models. Some early ’80s fronts were a CAD vacuum-disconnect design that should be avoided. Normally have to outboard the spring perches on CJ and YJ Jeeps unless narrowing long-side tube.

GM 14-bolt Rear

Found in:’73-’01 GM ¾- to 1-ton pickups, vans, Suburbans
Width between wheel mount surfaces: 67½ inches (pickup/Suburban); 70 inches (van); 72 inches (duallie pickup)
Shaft diameter/spline: 1.5-inch, 30-spline
Common gearing: 4.11, 4.56
Bolt pattern: 8-on-6½

Pros: You can find this 10.50-inch ring gear axle at virtually any junkyard and take it with you for $75-$200 depending on your location. Parts are easily obtained and it uses one of the least-expensive Detroit Lockers offered thanks to its sturdy factory split-case carrier. They’ll stand up to huge abuse and 44-inch tires in stock form.

Cons: The bottom of the differential hangs pretty low, so large tires or cutting the pumpkin are necessary for good ground clearance. The 1-ton drum brakes are massive, so swapping to aftermarket disc brake brackets with junkyard ½-ton calipers may be desired.

30-spline CJ Dana 44 rear

Found in: ’70½-’71 CJ (offset); ’72-’75 CJ, Jeepster/Commando (centered)
Width between wheel mount surfaces: 51 inches
Shaft diameter/spline: 1.31-inch, 30-spline
Common gearing: 3.73, 4.27, 4.88
Bolt pattern: 5-on-5½

Pros: The CJ versions are a bolt-in solution to virtually any ’75-earlier Jeep CJ that gets you one-piece, flanged 30-spline shafts inside a decent housing that’ll stand up to street driving and moderate off-roading. It’s a great find for street-driven restorations or vintage wheeling builds.

Cons: Some non-CJ/flatfender models may need axle pads moved. The ’70½-’71 offset models are becoming exceedingly rare and pricey. The narrow 51-inch width doesn’t make it a great choice for a hardcore build.

High-Pinion Dana 30

Found in: ’95½ -’00 Cherokee
Width between wheel mount surfaces: 60½ inches
Shaft diameter/spline: 1.16-inches, 27-spline
Common gearing: 3.55, 4.10
Bolt pattern: 5-on-4½

Pros: The ’95½ Cherokees got upgraded axleshaft U-joints from 260X to Dana 44-size 760X. That, coupled with a high-pinion design makes it a great bolt-in upgrade for the TJ Wrangler low-pinion or older Cherokee low-pinion or CAD front axles. You can also cut off the brackets and weld on spring perches for use in YJ vehicles without too much hassle.

Cons: The axletubes are somewhat weak, so you’ll want to at least bolster them with a set of EVO Sleeves from Off Road Evolution or build a truss to help survivability in heavy off-road use.

Disc-Brake CJ Dana 30

Found in: ’76-’81 Jeep CJ (narrow-track); ’81½-’86 CJ (wide-track)
Width between wheel mount surfaces: 51 inches (narrow-track); 56 inches (wide-track)
Shaft diameter/spline: 1.16-inch, 27-spline
Common gearing: 2.73, 3.54, 3.73, 4.09
Bolt pattern: 5-on-5½

Pros: With some slight work to accommodate the 2-inch-wide spring pads and steering, the open-knuckle, disc brake Dana 30 is a bolt-in upgrade for virtually any ’41-’76 drum-brake CJ or Universal. They’re good for tires of roughly 33 inches in stock trim, but can be upgraded with larger chromoly 30-spline aftermarket shafts to bump that up a bit.

Cons: Despite the potential for better-than-Dana 44 shaft strength, the low-pinion gearset will remain the weak point, so gnarly off-road builds with big tires aren’t for this axle. The narrow-track versions are best kept off the extreme rigs as well. Also, the later five-bolt external-body hubs require periodic bolt maintenance to ensure survivability.

31-spline Ford 8.8

Found in: ’95-up Ford Explorers
Width between wheel mount surfaces: 58¼ inches
Shaft diameter/spline: 1.32-inch, 31-spline
Common gearing: 3.73
Bolt pattern: 5-on-4½

Pros: They’re commonly found in junkyards and the ’95-up models have disc brakes, 31-spline shafts, and many have Trac-Lok differentials. The axletubes are beefy 3¼-inch suckers and the bolt pattern matches the YJ/TJ/XJ vehicles in which they’re normally swapped in as a Dana 35 replacement.

Cons: The axle is about 5⁄8-inch narrower per side, so wheel spacers are commonly needed to even things out front-to-back. The pinion yoke must be changed out or a conversion yoke/U-joint used to work with the Jeep driveshaft. New E-brake cables are also required, as are new brackets. Lastly, almost no Jeeps of this ilk came with 3.73 gears, so a ring and pinion swap is often required. By the time you’re done adding it all up, it becomes a very costly junkyard swap.

Ford 9-inch

Found in: ’74-’86 Ford F-150 pickup, Fullsize Bronco, E-150 vans
Width between wheel mount surfaces: 65 inches (pickup, Bronco); 68 inches (van)
Shaft diameter/spline: 1.20-inch, 28-spline; 1.30-inch, 31-spline
Common gearing: 3.00, 3.50, 3.55, 4.10
Bolt pattern: 5-on-5½

Pros: The 65-inch width of the more common pickup and Bronco is nearly perfect as a factory-replacement for J-trucks and wide-track Cherokees, while not too wide to prevent use in extreme CJ, YJ, and other builds. The gears are easy to set up and very strong, aftermarket 31-, 35-, and 40-spline axleshafts are abundant, and traction aiding devices can be had for as little as $20. Yeah, Google it.

Cons: Junkyard versions are starting to get a little scarce, especially the good “Camper Special” models with the Nodular centersection and 31-spline shafts. The pinion is very low, which can make for poor drivetrain angles in shorter-wheelbase vehicles. Most come with a funky Ford-spec 1330 U-joint yoke that needs to be swapped out or run with a conversion U-joint.

Toyota 8-inch Rear

Found in: ’79-’95 Toyota 4Runner/Pickup
Width between wheel mount surfaces: 55 inches (’79-’85 solid front axle); 58.5 inches (’86-’95 IFS front)
Shaft diameter/spline: 1.29-inch, 30-spline
Common gearing: 4.10
Bolt pattern: 6-on-5½

Pros: The Toyota axles have a drop-out centersection design much like a Ford 9-inch. The V-6 centersections are much stronger than the four-cylinder version, with larger bearings and extra webbing. The width of any of these rears would work well in the rear of a flattie or early Jeep running a centered T-case and a six-lug front.

Cons: They’re becoming less common in wrecking yards, but persistence definitely pays off. All will require cutting and welding for installation, as well as a pinion yoke swap or conversion yoke, e-brake modification, and possibly a gear swap.

Full Size Dana 60/Dana 70 rear

Found in: ¾- and 1-ton Dodge, Chevy, Ford 1-ton pickup and van.
Width between wheel mount surfaces: Between 66-70 inches
Shaft diameter/spline: 1.31-inch, 30-spline (3⁄4-ton Dana 60); 1.50-inch, 35-spline (some HD ¾-ton and 1-ton Dana 60 rear); 1.50-inch, 23-spline (early Dana 70); 1.50-inch 32-spline (’87-’02 Dodge Dana 70); 1.50-inch, 35-spline
Common gearing: 3.73, 4.10, 4.56
Bolt pattern: 8-on-6½

Pros: For a cheap rear axle you can slap in and flog, you can’t get much better. Even the full-float 30-spline Dana 60 will live up to some serious abuse. The 32- and 35-spline Dana 70s are as stout as anything you’re likely to find on the trail, but even if you desire or require them, aftermarket upgrade parts are available.

Cons: Many 30-spline Dana 60 axles require hogging the spindle bore to fit 1-ton-size 1.50-inch, 35-spline shafts. There are a dizzying number of different Dana 70 models out there, each requiring a different ring and pinion and axleshaft length, so research before you head out. The book Differentials, Identification, Restoration, & Repairs by Jim Allen and Randy Lyman is available through Randy’s Ring & Pinion (866/296-5721, ringpinion.com) and has a large section on identifying the different Dana 70 models.

Isuzu Dana 44 Rear

Found in: ’93-up Isuzu Rodeo/Honda Passport
Width between wheel mount surfaces: 58 inches
Shaft diameter/spline: 1.31-inch, 30-spline
Common gearing: 4.10, 4.30
Bolt pattern: 6-on-5½

Pros: It’s the right width to work in a TJ or YJ Wrangler, but isn’t so wide it looks out of place under an early Jeep if you’re running a centered rear axle. The six-lug bolt pattern is a curse, unless you’re also upgrading the front axle with a Wagoneer Dana 44 at the same time. Disc brakes and Trac-Loc diffs from the factory are plusses.

Cons: The six-lug bolt pattern will need to be redrilled or you’ll need to use new shafts if you’re trying to match your front five-lug bolt pattern. Most came with a funky driveshaft flange that’ll need to be swapped out to work with the Jeep’s U-jointed driveshaft.

Kingpin Dana 60 Front

Found in: ’77-’91 GM 1-ton pickups; ’78-’79 Ford F-350; ’77-’93 Dodge 1-ton pickups
Width between wheel mount surfaces: 67½ inches (Dodge); 69¼ (Ford); 69½ (GM)
Shaft diameter/spline: 1.50-inch, 35-spline
Common gearing: 4.10, 4.56
Bolt pattern: 8-on- 6½

Pros: You’re pretty much not going to find a stronger junkyard front axle to run in your Jeep. Burly housings, beefy shafts, a great ring and pinion, and huge brakes are just a couple selling points. Furthermore, the Ford versions are a high-pinion design that’s even stronger than the GM/Dodge versions. Ford will have a driver-side differential, while GM and Dodge are on the passenger-side.

Cons: Price, price, and price again. Good luck finding one of these in the junkyard. This author has only seen one once, and shortly after it arrived a fist fight broke out around the K30 housing it.

Honorable Mention
We just don’t have room to run every cool junkyard axle swap, so here’s some more food for thought.

The more-modern ball joint Dana 60s are now starting to worm their way into wrecking yards. The ’80-’98 F-350 Dana 60s have driver-drop differentials and high-pinion centersections, and locking hubs.

Ford Super Duty Dana 50 and Dana 60 axles? There are millions of ’em. The Dana 50s have 30-spline shafts, but large U-joints and a good high-pinion centersection. The brakes are massive and they have locking hubs.

The ’94-up Dodge Ram ½-ton Dana 44 and Dana 60 front axles are pretty wide, but they’re all over the junkyard nowadays. Again, driver-drop diff. Why not sling one under a YJ or that later FSJ project? The only bummer is the lack of locking hubs, but the ’94-up versions don’t suffer from the same problematic unit bearing design as the older ’70s Dodge axles.

We kind of skipped over the high-pinion Ford Dana 44 axles from the ’70s. The trouble is, many were equipped with huge C-bushing suspension mounts that may or may not be an integral part of the axle tube. Sometimes retubing is required if you want to shorten or remove the C-bushing mounts.

Finally, we ran with a Toyota 8-inch rear, but not the front. Toyota sheetmetal front housings didn’t really get good ’till the last-year ’85 models and by then it was all over. They’re hard to find and chances are some Toyota guy swooped you at the junkyard. Expect to find dangling, bare leaf springs. Earlier axles would require gusseting to prevent bending and all suffered from a relatively weak Birfield shaft. You can upgrade the shafts, but if you’re going to go through all that trouble on a closed-knuckle axle, why not start with something better like a wide-track Dana 30, Wagoneer Dana 44, or other option we listed, right?

Related Articles

Comments

Connect With Us

Newsletter Sign Up

Subscribe to the Magazine

Sponsored Content