Step By Step
Factory tags like this one can be found in the glovebox of GM trucks. They list all the options a truck has and can be helpful in deciphering what axle ratio the truck came with or even if it has a limited slip. Ford codes this information and puts it on the gross vehicle weight rating (GVWR) plate on the driver-side doorjamb. Dodge trucks are the easiest to figure out because they spell out exactly what axles and gears a truck has with a tag located on the underside of the hood. Buyers beware though, because everything is not always as it appears. Stickers like this could be missing, faded, or even wrong if a previous owner swapped hardware.
Heres how you can score a full-floating GM 14-bolt with 4.10 gears for $75. If you are building up a 1/2-ton truck then look for a 73-83 3/4-ton Suburban or pickup like we found. The 14-bolts from these trucks will have the spring perches in the same place as your 1/2-ton axle. A 14-bolt from a van is 3 inches wider than a pickup or Blazer, and can be used to widen the rear track width of your truck. However, to use the van housing you will have to move the spring perches. Pull the differential cover to make sure everything is still there and that it doesnt have a Gov-Loc. Remember, a Detroit Locker ($328) will only bolt into an open carrier. By pulling the axle from the truck yourself you can save money and get a feel for what type of life the axle has led.
Want to go even bigger? Try this Eaton full-floating axle out of 62-72 GM 3/4-tons. These 12 1/4-inch ring gear monsters have both a drop-out centersection (like a Ford 9-inch) and a removable rear cover. These axles use 1.55-inch-diameter shafts but are only 17-spline where they mesh with the differential. Ratios are 4.57s or 5.14s, and some 69-72 trucks had factory installed Detroit Lockers in them. (Tractech has discontinued this partso you better find a used one.) Two-wheel-drive versions like the one shown came with trailing arms and coil springs, which is a great start if you want to get rid of your leaf springs.
The Ford 9-inch has been used in every form of motorsports there is. Unless you are building a 1/2-ton Ford, chances are you will need a good core. Look for axles like this one under a Lincoln Continental that has led a very easy life. These housings actually have more metal in them (they are stronger) than the truck versions. Most luxury cars like this will have a factory-installed limited slip, but chances are equally good that it will have really high gears in it too.
Good parts go fast at the junkyard. This GM 3/4-ton Dana 44 was missing its spindles and hubs by the time we found it. We wanted the whole assembly, but grabbed the long axleshaft to use as a trail spare.
These four axleshafts from front to back are: a 1.31-inch 16-spline Dana 60, a 1.31-inch 30-spline Dana 60, a 1.50-inch 30-spline 14-bolt, and a 1.50-inch 35-spline Dana 70. All of these rear axles were used in 3/4- and 1-ton trucks so make sure you know what you are getting and pull one of the shafts before you plunk down any cash.
This is a Dana 60 from a 77 B300 Dodge van that was converted into a camper. Stay away from axles that look like they have been supporting their maximum rated load for their entire life. See those overload springs on the shocks? Thats a sign that this truck was always loaded downlet someone else buy this baby!
One of the reasons Ford 9-inch axles are so popular is because the entire third member (differential, ring gear, pinion gear, and bearings) unbolts from the housing. This makes the axle very easy to work on as you can set up new gears without having to deal with the rest of the axle assembly. In this photo you can see the extra pinion bearing that these axles use to keep the pinion gear in contact with the ring gear. If you need to add brackets for links or traction bars to these axles it is super easy because the housing is steel and not cast iron. And Ford 9-inchers are totally modular, meaning you can convert even the weakest 28-spline, 1.20-inch axleshaft piece into a full race 40-spline shaft deal with bolt-on parts.
You want to talk rare? This is a complete 35-spline Dana 70 front axle with open knuckles that will be used in a 4x4 motor home. You dont have to drool too much, because the only difference between it and the GM Dana 60 next to it is the ring gear diameter. Most Dana 70 front axles we see have closed knuckles and drum brakes and use 23-spline shafts. You can pass on these guys because they are from mid-70s Dodge trucks. The closed knuckle axles hold steering U-joints that are the same size as Dana 44 pieces. Even if the price seems dirt cheap, make sure you are getting something you can use.
Dana 60 and Dana 70 axles both use the same differential cover even though the Dana 70 has a 10.54-inch ring gear versus the 9.75-inch ring gear of the Dana 60. Look in the lower right-hand corner of the housing to find the cast-in number to tell you which one you have. If there is no number, then it is cast into the pinion support on the backside of the axle. This is a photo of a Dana 70 axle. Notice the extra material on the flange that extends further than the steel differential cover. Dana 60s wont have this extra lip.
In 1985 Ford began offering its own axle (built by Sterling) in the form of a full-floating 10.25-inch ring gear axle with 35-spline 1.50-inch shafts. When Ford redesigned the Super Duty in 1999 it increased the ring gear diameter of this axle to 10.50 inches. Most people think that 4.56s are the lowest gears you can run in these axles, but 7.17s are available under the Ford PN E5TW4209FA. If you are thinking about using one of these for your next project, get the full-floating axle, as there is also a C-clip version of the 10.25-inch that was used in some light 3/4-ton trucks. This photo shows Fords new 9.75-inch axle that it uses in V-8 F-150s and Expeditions. These axles come with 34-spline shafts and have been used since 1997.
If the tag is still there, finding out what hides beneath the differential cover is easy on a Ford. Look at the lower row of numbers on this tag: 3L55 9 75. These numbers signify a gear ratio of 3.55:1 (the L between the 3 and the 5 means it has a limited slip) and the 9 75 means it has a 9.75-inch ring gear.
So its Saturday morning and youre wearing your oldest, dirtiest, greasiest clothes because you are headed for the junkyard to get some new axles. What you come home with depends on whether or not you know what youre looking for, and what kind of trucks you have at your local auto recycler.
Without even consulting our Magic 8 Ball, we can tell you right now that no matter where you live, you are going to find fullsize trucks that are rusted out, broken down, or just plain tired. These trucks were made to give up their axles, so consider it your duty to recycle their best parts and score yourself some new iron.
Axles are usually priced based on whether they are ½-, ¾-, or 1-ton parts. Arm yourself with a tape measure and something to write on so that you can compare the dimensions of the stuff you find with the dimensions of the stuff you have. Make sure to bring all of your ½-inch drive sockets and breaker bars because youre dealing with heavy assemblies here and a 3/8-inch ratchet isnt going to bring home that Dana 60 sitting under the front of that K30.
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