Ever since I built it, my Dana 60 has been running the same set of OE 35-spline, 1 1/2-inch-diameter Spicer axleshafts and Spicer 5-332X U-Joints. The lefthand (short) axle was the stock length, but the righthand (long) side had been cut down and resplined. The outer stubs were upgraded to Chevy 35-splines also. I never had a failure, but every time I put those 40-inch IROKS against a wall and nudged the skinny pedal, I held my breath, waiting for that familiar sound. Upon disassembly to install the Reid Racing knuckles, I found that I wouldn't have had to hold my breath much longer. The cut-down respline was twisting, and a few more walls and--pop! It was time to upgrade the axles as well. The 4340 chromoly axleshafts are all the buzz these days and have pretty much become the norm for custom-length applications. Only the mega-bucks unobtanium 300M axles used by the top rock racers are stronger. The 4340 chromoly 'shafts offer up to 35 percent greater strength than OE units. For the recreational wheeler with Dana 60s, this kind of strength should mean years of trouble-free axle life. I went to Alloy USA for my trouble-free axles. Alloy can provide 4340 chromoly inner and outer 'shafts in stock or custom lengths. These axles feature extra material in the critical U-joint yoke area and dual heat-treating of the entire axle. The yokes are machined for full-circle U-joint retaining clips as well.
Like with most upgrades, one thing lends itself to another. Having chromoly axleshafts just screams for upgraded U-joints as well. Why have extra-strong axles and weak OE U-joints? To complement my alloy axles, I joined them together with CTM U-joints. CTM and the word "indestructible" are synonymous. CTM U-joints were the first heavy-duty axle U-joints and they have a proven track record with most of the top teams in professional rock racing. These things don't break, and it would be foolish to run chromoly axles without them. On the flip side, they should not be used with stock axles as they are made from such a stronger material, they could cause premature failure of the OE axleshaft. Check out the photos of how these U-joints are installed. So the recreating of this old Willys continues on. Who knows what it will "bee" in another 30 years? I know one thing--these Reid Racing/Alloy/CTM upgrades will probably still be hauling it over the next rock pile.
Note the extra amount of material in the area of the crack. Between the added material and the fact that the knuckle is made from a higher strength nodular iron than the OE issue, I don't expect to see a crack like this again. Also note that the old knuckle has had its four high steering-arm studs drilled and tapped from 1/2 inch to 5/8 inch. This is because the four 1/2-inch units failed several years ago, coming loose and shearing off. | 
Reid Racing addresses the option of using high-steer components by adding a lot more material to the top of the knuckle and providing a fifth mounting hole. The OE knuckles were never designed to handle high steer and this is probably why I had the shearing problem in the past. Also note the ribbing added in the area when the OE piece cracked. | 
I utilized these high-steer arms available from Dynatrac. They can be purchased as blanks so you can drill and shape them to your liking. In the background is the righthand arm mounted to the Reid Racing knuckle with five 1/2-inch studs and drilled for my tie rod, which features 3/4-inch Heim joints. In the foreground is the blank for the left side, which still needs to be shaped and drilled for the fifth hole and the tie-rod hole. Below it is the orange arm cast into the Reid Racing knuckle which I feel is too low for big-rock wheeling. Using this mounting location for your tie rod would just be asking for a big rock kiss. I'll eventually cut these arms off the knuckles for a cleaner look. |
Since I had the axles out to replace the knuckles, it was a good time to take a look at them. Although I'd never had a failure of the stock Spicer shafts (which were new several years ago when I built the axle), I was about ready to. Note the twist starting to form in the splines of the righthand inner axle. These were cut splines since this was a custom-length axle. Since the Spicer axles are mild steel and the hardening doesn't run too deep, this spline twisting is what happens after a while. | 
This is the answer to twisted splines. Alloy USA chromoly axleshafts coupled with CTM U-joints. | 
CTMs are fully rebuildable and don't have any needle bearings to crush or contaminate. Like any high-performance part, they require a bit more maintenance in that they have to be greased fairly often. If you've ever grenaded a needle-bearing U-joint and wiped out an axle yoke in the process, you know that this maintenance is a small price to pay. |
Here is a comparison between the OE Spicer axle on the left and the Alloy/CTM unit on the right. This picture paints a thousand words as you can see the extra beef in both the axle yokes and the U-joints. Couple that beef with the far superior materials the aftermarket parts are made of, and you can see how racing has improved the breed, providing 'wheelers with parts that will last longer than the period of time some of us have dreamed about their coming into existence in the first place. | | |