CTM Heavy Duty Universal Joints
by Andrew Horvath
Having a dependable rig means your driving gets 100% of your concentration, which doesn't happen too often on the trail. When you ask a fellow wheeler about the item on his truck that he is most worried about when running hard trails, the most common response is, "my axle shafts and u-joints." When people consider upgrading an axle they tend to think about getting high strength alloy shafts and then just using a stock u-joint. This combo may be a bit stronger but the fact still remains that the regular replacement u-joints love to blow up which usually results in the deformation of the (expensive) alloy shafts in the process. Now the obvious solution for many is to upgrade to a larger axle assembly. In the case of the very common and popular Dana 44, the most likely upgrade path is to the Dana 60. A Dana 60 is a Dana 60, there is no way to get around the strength benefits of this differential. However there are many factors to weigh before making the choice to swap. Dana 60 front axles are not plentiful on the used market and consequently are quite pricey. Other possible negative factors are the higher cost of brake parts, gears, lockers and steering. You get the idea right? Now add in the fact that you've already spent a sizable chunk of change upgrading the diff, gears, and steering on your D44! And on top of all that, you might also have to narrow it (there are no narrow Dana 60's...and shortening the axle means you'll still need custom axleshafts); you will lose ground clearance; and you'll be adding extra weight to your 4x4. For some swapping to a Dana 60 will make a lot of sense, but for most it will be a prohibitively expensive way to upgrade.
The solution to the weak Spicer u-joints? The CTM Heavy Duty Universal Joint.
Where's the beef?
You're probably wondering how much stronger this u-joint can be, right? After all metal is metal. Well, in actuality, part of the secret IS in the metal. The material that Jack (owner of CTM) uses to manufacture his CTM u-joints is a high strength 300M-alloy steel. The process that is used to create these joints is very involved and all steps are critical to ensure a bulletproof product. The u-joints are first forged into shape, then cut, cryogenically frozen, heat treated and finally finish-machined. When you hold a CTM u-joint up against the tried and true Spicer 760X you can see the difference in strength right away. Another major strength gain lies in the fact that the CTM uses a bronze sleeve rather than the needle bearings found in a 760X. The absence of the needle bearings allows the CTM u-joint to be made with a larger cross that is actually the same size as a Dana 60 joint. And finally, the last really significant part of this joint is that it is designed to use full circle clips to retain the u-joint in the shaft rather than the half clips that come with Spicer u-joints (yes, this requires a custom axle shaft but who in their right mind would upgrade to a super heavy duty u-joint without changing shafts at the same time?). Believe it or not these full circle clips add a lot of strength to the combo because they prevent the cap from walking out which is perhaps the most common cause of u-joint failure.
Lets talk numbers here. You want to know just how much stronger this set-up is over a stock shaft/u-joint right? Well the yield strength of a Warn chromoly axle is approximately 230,000 psi versus the 90,000 psi yield of a stock Spicer shaft in brand new condition (not a 20 yr old shaft like most of us run). Now the psi yield strength of the CTM is in the neighborhood of 300,000 psi, which far beyond the strength of the Spicer 760X. In short, the Warn alloy shaft is a much better match with the CTM u-joint.
Another feature about the CTM u-joint that most people forget when they are comparing it to a Dana 60 in strength is that the u-joint posts are the same size but the CTM is created from a far superior material. A point I'd like to address is the claim that Warn shafts aren't that strong because people have twisted the splines of these shafts. What they fail to understand is that the twisting of the splines is caused when the Spicer u-joint lets go and releases all the stored energy in the shaft. This isn't a result of normal operating stress. With a CTM u-joint in place this generally becomes a non-issue because it takes far, far more stress to break the joint.
After you finish admiring the beautiful workmanship of these u-joints and convince yourself to install them in a place where they are surely going to get abused, you need to follow some very important steps to ensure a long and trouble-free life of the u-joint. The steps are very similar to installing a regular needle bearing u-joint but in my eyes it is much easier because you don't need to worry about keeping all the needles in place. I can't count how many times I have dropped those little needle bearings on the ground or even had to use a new cap because I messed them up during installation.
The first step in the installation process is the removal of only two of the caps making sure the caps are opposite one another. After you have done this you need to add a snap ring and an o-ring over both the ears. The next step is to slide the u-joint into the shaft, which takes a little effort. When sliding the u-joint into the shaft, make sure the ear that has a little clearance groove in it goes in first. Even with this clearance groove you may need to tap the u-joint with a BRASS mallet to pop it into place.
After you have the u-joint in the axle shaft you need to carefully place one of the caps into the axle shaft ear and align it with the u-joint. Now you want to carefully press the cap into the shaft ensuring that the cap goes in straight. The most controlled way to do this is to use a 5" vise that is firmly anchored to a bench. Once the cap is pressed all the way in, seat the snap ring into the groove that is machined into the cap. Next, start to install the opposite cap into the axle, once again ensuring the cap is lined up with the u-joint.
Now that the u-joint is installed in one of the shafts, it is time to install the other half in the other shaft. The steps that you need to follow are the same as above but you will have a little more trouble because you have a heavy axle shaft flopping around when you are trying to line up caps and u-joints. After doing the first shaft I found it easier to install only one of the snap rings and o-rings on the u-joint before installing the cap. After the 3rd cap was installed I added the rings to the other side and pressed the 4th cap in. I did this to make things a little easier and it seemed to work quite well. Now that you have the u-joint installed double check that all the snap rings are properly seated and get ready to do the next shaft.
So now that you have both u-joints installed into the shafts it is time to install them into your axle. I should mention that those 8 little grease nipples will be installed after the shafts are through the knuckle. This is because the size of the axle and CTM will not allow you to slide the assembly in if the nipples are installed. So once you have the shafts in place and the outers installed on your D44 it is time to thread in the little nipples. Once you install the nipples get out the grease gun right away before you forget.
On my first run out armed with these awesome u-joints in the Jeep, I tried my hardest to explode the Warn shafts and CTM u-joints. The trail that we ran was a newly discovered trail that is one of the most difficult around here. One of the things that make this trail difficult is the steepness of the rocks. Sceptics will assume that there was little chance of breakage because most of my Jeep's weight was on the rear axles, right? Well, I considered that and assumed that going up would be a warm up and the real test would be when I came back down. Going downhill, most of the vehicle weight is on the front axle. In this situation, if you need to back up and crank your tires to the side, your chances of snapping an axle shaft will skyrocket. So how did I test these joints? All day long coming down this extremely technical trail I was forced to back up with the tires cranked. So in the interests of testing the CTM joints, I put my Jeep, (which is equipped with 38" SX's, a very healthy 275hp 5.0 HO, and dual transfer cases), in low-low (160:1 reduction) and hammered on the gas. I did this several times on various sections of the trail. If any other u-joint was in the Warn shafts, I would be willing to bet that I would have gone through at least a handful of them during this torture test. But with the CTM joints, my Jeep suffered zero damage. I was thoroughly impressed.
Anyone who's into hardcore 'wheeling MUST consider using the CTM joints. They allow you to run a lighter axle and retain your investment in your Dana 44 (and your ground clearance) while giving you a tremendous improvement in axle strength. And remember, it is ALWAYS cheaper to upgrade than to repair breakage, not to mention the lost recreational time spent on trail repairs.
So now that you think these u-joints are the best thing you can do for your D44, I should mention the best part about these joints. If you ever manage to break one of the u-joints, send it back to Jack and he will replace it free of charge! Can you believe it, a bulletproof u-joint with a lifetime warranty.
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