Dana 30 CV axle options
 

I'm just attempting to put some basic info together to help anyone doing a search for this. Any additional info or comments on performance/quality are welcome! I will not be including anything about the RCV Shafts as those are more for serious off roading and very demanding applications.

The Dana 30 front axle in the XJ came with u-joint axle shafts from the factory. U-joints are great but some people like to switch to CV axles for a number of reasons.
For example, if/when a CV axle breaks - it shouldn't do any harm to your knuckle or ball joints and you can probably limp out of the spot your in or even make it home. They are known to have a smoother feel when turning. In a straight line they are not as strong as a u-joint, so there is some compromise.

The general part numbers for our XJ Dana 30 are CH8220 (drivers side - short) and CH8221 (passengers side - long). The first thing google pulls up is O'Reilly Auto Parts with there Precision CV Shaft brand but this part number applies across brand names. I am sure there are more than a couple different manufacturers of CV axles shafts and I am also sure that many of the options are made by the same company. For example, I have read that Precision CV shafts are made by Trakmotive. I have no real evidence to support this. These shaft have ABS rings on them but will work with non-ABS jeeps also.

I have noticed that there is a "standard" and a "HD" or "fleet" version of these part numbers depending on the brand. And there are actually differences according to the Trakmotive tech department. See findings at bottom of post update!

O'Reilly Precision CV Axle Shaft CH8220 is considered a standard shaft. If you search for the CH8220C you will find they have it and the only visible difference is the style of boot.
The "standard" has a neoprene boot and the "C" version has a thermoplastic boot. See pictures below.

https://cimg9.ibsrv.net/gimg/www.che...cbd1ea7263.png
https://cimg8.ibsrv.net/gimg/www.che...30cdfa6183.png




The same thing applies to the Trakmotive brand. They have a CH8220/CH8221 and also a CH8220HDX/CH8221HDX. The HDX uses the thermoplastic boot while the standard uses neoprene. The specs are identical to the Precision brand. Trakmotive does say the country of origin is China.

According to the Trakmotive details on these options, the HDX (or the O'Reilly "C" version) is better for very cold environments with its thermoplastic boot and its specially formulated 7023B grease with temp range -40 F - +280 F. The thermoplastic boot is supposed to more resistant to cuts or tears when compared to neoprene. If you want to dive into the super duper detailed scientific stuff - search for TPE or thermoplastic elastomer boots and you can go down a rabbit hole.




https://cimg6.ibsrv.net/gimg/www.che...97b7995699.png







https://cimg5.ibsrv.net/gimg/www.che...3c0448117b.png


Both of these brands offer a lifetime warranty (I do not know the details). There is a considerable price difference between these brands and both have a good reputation. Personally, I went with Trakmotive from Rock Auto.

One thing worthy of mention is I do see a physical difference. If you look closely where the small end of the boot clamps to the shaft, the shaft does reduce in diameter at the clamp location. I don't have both option on hand to measure the physical difference, so this may just be a perceptual difference and not actual.. But the O'Reilly "C" version and the Trakmotive "HDX" version appear to have a larger diameter or less of a necking down where the small end boot clamp is located. Measurements pending...

LUNCHTIME UPDATE - I called the Trakmotive phone number from the warranty sheet 1-855-831-9444 and the automated message says, "Thank you for calling Advanced Innovative Technology". I am guessing that is the parent company of Trakmotive.
I spoke with the tech department about the difference between the standard CH8220 and the CH8220HDX. The rep told me the shafts are the same sizes, the difference is the joint, the lubricant, and the boot. He said the standard CH8220 is a 6 ball joint with basic grease and neoprene boot. The CH8220HDX is a 8 ball joint with the special 7023B grease and the thermoplastic boot.


If you have and more info or details on brands or the different options please share your info here!

Nice summary. Others have said that the shaft does neck down a bit around the actual CV joint. Would be interesting if the C/HDX version does not have this feature.

They do neck down some. If you look closely at the pictures you can see it. When I get home this afternoon, I can measure the shaft at that location and see what it is. Hopefully someone with a standard version can do the same and we can know if there is any difference..

Once I have the measurements and know of any difference I will update the original post!

So I was able to measure the Trakmotive HDX CV shaft compared to the original ujoint shaft. My digital calipers battery was trying to die on me and the screen was flashing but I'm pretty sure I got good measurements BUT I did not get all the measurements I wanted to (main shaft and sealing surfaces). I will revise after battery swap and confirm the calipers are measuring correctly.

UPDATE- Changed the battery out and measured everything again. I measured only the passengers side (Long) shafts... Below is what I found...


Trakmotive HDX CV shaft:
Diff side splines- 1.160"
Neck down before diff splines- 1.113"
Axle seal surface- 1.194"
Main shaft- 1.225"
Neck down at CV joint- 1.085"
Hub side splines-1.160"

Stock ujoint shaft:
Diff side splines- 1.160"
Neck down before diff splines- 1.114"
Axle seal surface- 1.195"
Main shaft-1.225"
Neck down before hub splines- 1.051"
Hub side splines-1.155"

Three comments/questions:

- For comparison to stock u-joint axles, the material of construction matters substantially. OE axles are likely make from a much cleaner alloy than Chinese-made axles and could easily be stronger even if the neckdown cross section is significantly smaller than a Trakmotive axle.

- Can you measure a Trakmotive non-HDX CV axle too to verify it is dimensionally the same as the HDX?

- What typically fails when a CV axle in an XJ breaks? Does the shaft fracture, or does the CV shred?

I read on the Trakmotive site the shafts are made of new "steel".. Which specific alloy of steel is not mentioned. I would think the OEM u joint shaft is by far a stronger shaft. Or if one could be found, an OEM CV shaft out of the Grand Cherokee would be stronger than any of these aftermarket CV shafts.

I hope someone who has a standard grade CV shaft can take some measurements. Then we'll know for certain.

My understanding is, in general, the CV joint itself is the failure point more so than the shaft. Torn or cut boots allow grit and debris into the joint and its eats away at everything until the connection between the both sides is compromised.

Did you ever put these axles in?

Yes I did! With great results. Install was smooth (at the time I had just re-sealed the front axle and installed new knuckles and hubs), but they slid right in and fit great.

They feel very smooth when turning sharply and so far have not let me down in 4x4.

Total happy with them.

DeXJ recently posted on FB asking people for their experience with the CV axles. There was a huge range of responses - everything from being able to handle tons of abuse to breaking when driving up a smooth fireroad. My suspicion is that a common denominator for breakage is using these with locking diffs. And its always the axle that breaks, not the CV.

Interestingly, there was one guy who broke a spindle multiple times. Seems he's seen it happen not only on his rig but others, but only during offroad. Pretty scary to consider if it were to happen on-road.

It was my understanding that a locking front diff was "easier" on the axles/joints,, ?
As the torque is consistently, evenly spread between the 2 sides,, while an open diff can get in a situation where all the power is sent to the side slipping,, spinning at full throttle, then that side bites, sending power to the "idle" side,,,

I suppose that is a valid scenario for creating an impact loading on the axle shafts, but I have no idea how easily that scenario occurs. Nothing like that has ever happened to me on the street or in the dirt. Maybe something that can happen during rock crawling with an open diff.

An open diff always sends the same amount of torque to both sides, a locker sends far greater amount of torque to the wheel with the most traction.

What did you use for axle tube seals?
Got any pics of your new set up?

I recently swapped in a set of the HD axles that I purchased off Rockauto, Trakmotive CH8221HDX and CH8220HDX. I've probably got 2k miles on them now, so far so good, but I am not an aggressive off roader. Having just found this thread, I'm glad I didn't pay extra just for different boots and grease.

Two things to note based on installing them into a '99 XJ high pinion axle, but I imagine this is universal.
1. The CV boot clamp was too large to fit through the axle C as delivered. I gently tapped the crimp down with a hammer until it cleared.
2. They do not come with the axle shaft dust shields, if you want them buy new ones or transfer over your originals. I bought some 2 piece ones that clip together to put on already installed axles, and found they were too large to fit between the CV boot and the axle C.

The uneven rotational speed of U joints at high steering angles was very obvious with my AX15 and NP242 combo when running in full time mode. CVs completely eliminated that. I had just replaced one u joint due to seal failure rusting out the joint. I'm glad that won't be a concern any more.