Sean P. Holman
Contributor
A question we seem to get a lot is from readers wondering if it is better to order a custom axle for their 4x4 or to buy a used housing and rebuild it to their own specification. It is a question that we didn’t always have an immediate answer for, but were curious about ourselves. So we decided to do a little research and put together a comparison as apples-to-apples as possible to help answer this lingering question: “Is it better to buy a custom axle or rebuild a used one?”
For the purposes of this story, we imagined a Chevy K10 pickup or K5 Blazer with 38-inch tires. The owner has already swapped an eight-lug rear axle in, and has now turned his attention to the front with the idea of having a stout, but not crazily overbuilt, front axle that has an eight-lug bolt pattern to match his rear axles, thereby keeping his wheels the same.
Depending on year, this generation of GM truck came from the factory with either a 10-bolt or a Dana 44 front axle, and for our fictional truck we would require a Dana 60 or comparable axle. It just so happens that Dana 60 front axles were available on 1-ton Chevys of the same vintage and are a nearly bolt-on affair, giving us two options for our exercise: choose an OE Dana 60 from a mid-’80s Chevy K30 or order a custom-built Dynatrac ProRock 60 to spec. Because we thought of the subject of this story as being a dual-purpose rig that would see pavement and dirt, we spec’d out both axles with a selectable ARB Air Locker. Also, keep in mind that much of the information contained in this story will apply to other vehicles, especially Dodge’s of the same era.
So what would the differences be between the junkyard axle and the custom axle? To answer these questions we headed over to axle manufacturer Dynatrac in Huntington Beach, California, to get a better understanding of what Dynatrac has to offer in a custom axle. Armed with that information, we then contacted the driveline experts at West Coast Differentials (WCD) in Rancho Cordova, California, and put an order in for our fictitious axle as if we’d be dropping it off to their service shop to be rebuilt.
Read on to see what we discovered.
Dynatrac 60
Dynatrac axles aren’t cheap, but they are among the highest quality aftermarket axles in the business and they are made here in the U.S. using parts from U.S. suppliers and raw materials that can be traced back to U.S. origins. All of the machining, heat-treating, finishing, and final assembly is done right here in the U.S. with the final product strictly screened for quality control. So what do you get when you purchase a Dynatrac axle?
The standard Pro Series 60 front axle comes with a high-pinion centersection, 31⁄8-inch-diameter, 1⁄2-inch-wall tubes, 1310 yoke, your choice of gear ratio, OE ball joints, 35-spline 1541 steel shafts, 35-spline stub shafts, 1480 U-joints, Warn Premium hubs, a Dynatrac nodular iron diff cover, and 13.1-inch brake rotors with two-piston Ford calipers. This basic open-knuckle axle is available for $5,395.
For that price, you also get a level of customizability, not available with an OE axle. Dynatrac can adjust steering geometry, as well as spring pad angle, and even overall width to give you exactly what you need and ensure your caster and pinion angle play nice with each other.
Extra-cost options that we decided to include on this build were the additional $299 to turn it in to a high-clearance ProRock 60 housing, the installation of an ARB Air Locker for $854, and a 1350 yoke for $29. Those items bring the total cost of our custom axle to $6,577.
Many stock ½-ton trucks came from the factory with Dana 44 front axles. While the 44 is a great axle in its own right, modified full-size trucks running upsized wheels and tires, big power, or lots of weight should consider the 1-ton-rated Dana 60.
Other options available that we did not include in our fictional build were Dynatrac’s massive 14.5-inch brake upgrade ($895), 4340 axleshaft and U-joint upgrade ($1,295), DynaLoc hubs ($429), and Dynatrac ProSteer rebuildable ball joints ($569).
No matter what upgrades you choose, Dynatrac offers a 12-month/unlimited mileage “no fault” warranty as well as some of the best customer service in the business.
Rebuilt Axle
Once we knew what the price and features of a custom axle are, it was time to build an OE axle as close as possible to Dynatrac’s 60 and see where we would end up. Our imaginary Dana 60 came out of the front of a mid-’80s Chevy K30 1-ton and is in good shape with straight tubes and perfect bearing surfaces that haven’t be wallowed out—a problem that might rear its head on abused axles. After checking around for pricing, the going rate for an axle like this is about $1,100, which will be the jumping off point for this part of our story.
The benefit of a ProRock housing over a standard 60 is the increase in ground clearance. In fact, the ProRock 60 has greater ground clearance than a Dana 44.
What you get with the OE Dana 60 is a stout, low-pinion axle with 31⁄8 inch tubes, kingpin steering, and single-piston brake calipers with the weakest link arguably being the “necked-down” 30-spline outer stub shafts. Assuming the axle has been sitting out, it will need to be professionally gone through, so we commissioned a shop quote from WCD for a complete hub-to-hub rebuild of our axle, along with some important upgrades that would bring it in line with the parts on the Dynatrac axle.
Assuming we dropped the axle off to the service department for them to do the work, we’d be spending $500 in labor for the rebuild. To the stock axle we’d add a ring and pinion, a master rebuild kit, 1350 yoke, 35-spline stub shafts, Warn Premium hubs, 1480 U-joints, kingpin rebuild kits, a front hub rebuild kit, ARB differential and cover, and OE Dana spindles with new seals and bearings. These items together would equal $3,687 in parts, bringing our expenditure after WCD to $5,287. WCD also includes a warranty against manufacturer’s defects and labor for one year.
Here you can see Dynatrac’s 1540 shaft next to the OE shaft. Not only is it stronger, but also it includes machining for a full snap ring, versus the OE’s machining for a partial snap ring.
Because WCD does not stock brake parts, we checked around for pricing on OE single-piston calipers, pads, and rotors online and came up with an additional $550 in parts (although pricing varies greatly), bringing our total outlay on the OE axle to $5,837.
This of course is a worst-case scenario. If you are competent in your differential rebuilding skills, you can save $500 in labor by doing it yourself. Another $500 can be saved if the OE axle only requires bearings and seals, but not spindles and you can save even more by going with aftermarket or junkyard brakes. For budgetary reasons, we chose to retain the OE 1040 steel axleshafts, which would be perfectly adequate for this build, although Dynatrac did include stronger 1541 steel shafts in its pricing.
Dynatrac’s standard brake package uses 13.1-inch rotors and two-piston Ford calipers with readily available pads. For those wanting to run 15-inch wheels, the company can also do an 11.5-inch rotor. Other braking options include 13.8-inch or 14.5-inch rotors.
So What’s the Answer?
In the end, the decision hinges on a number of factors that can’t all be accounted for in an exercise like this. It will depend on your overall budget, your needs from the final result, and how good of condition the donor axle is in. Personal preference may also come in to play if you prefer kingpins to ball joints, a high-pinion over a low-pinion, or the ability to have, or upgrade to, bigger brakes.
The major benefits to going with a custom axle, such as the one in this story from Dynatrac, is that the Dynatrac price includes a brand new axle, upgraded axleshafts and better brakes over stock, custom overall width and geometry, and the ability to spec out your axle exactly how you want it.
Now before you start writing your letters telling us how you could build an axle for this swap with a the cash you found in your couch cushions and a case of Pabst Blue Ribbon, just remember the goal of this story was to have as to close of a comparison as possible. We understand there are cheaper ways to end up with an axle, but at the conclusion of this exercise we have two totally comparable axles, built with as many new, equal parts as possible, and brought up to a similar standard, making this as fair a comparison as you can get. So while we can’t give you a definitive answer on which way to go on this one, hopefully we’ve provided you with enough information to make an educated decision based on your needs.
Side by Side Comparison Dynatrac PR60F Rebuilt OE Price $6,577 $5,837 Pinion High Low Tube Diameter 31⁄8-inch 31⁄8-inch Tube Thickness ½-inch ½-inch Knuckle Open Open Steering Ball Joint Kingpin Differential ARB ARB U-Joints 1480 1480 Yoke 1350 1350 Axleshaft 35-spline, 1541 35-spline, 1040 Stub Shafts 35-spline 35-spline Hubs Warn Premium Warn Premium Rotors 13.1-inch 13.0-inch Calipers Dual Piston Single Piston Warranty 12 mo/unlimited 12 mo labor/mfg defect
