Yes, I have been advised by many not to spend money on a semi float 60, as they say it is not a cost effective upgrade over a built 44. I understand the fundamental differences, but I also have some questions. From what I have read, the 44 axles breaking are quite frequently due to housing / deflection. With a stronger housing and differential in the 60, and running 35 spline shafts, I would think there would be a considerable upgrade in strength as compared to a 44. Why is this not considered a justifiable upgrade?

My wheeling will be limited to trails, mudding, and sand here in Florida, with some minor rock garden play. Why would a semi float not be sufficient for these applications? I am over budget on my build as is, and I can save several thousand utilizing a semi float rear.

All are welcome to chime in with their opinions, of course, but I would especially like to hear from those who are, or have in the past, run a semi float 60. Were you wheeling hard when you broke it? Did the entire wheel assly fall off? Would you make the same decision again?

Sorry to add another semi float post, but I could find nothing that specifically addressed these axles in the same manner as above.

Thanks!

 

It would cause the rear axle flanges to still be able to bend as the load is still on the shaft not the axle spindle. On a non jk semi float i have personally seen one rear wheel rip fully off and it was 35" tire., but it was at a werock event. I bent flanges on 35s on minimal hits i cant imagine running 37s or 40s on a semi float 60...





This was a moser axle but same principal.

http://www.moserengineering.com/comp...d-package.html

 

Would the flanges not also be larger on a 35 spline axle set up?

 

If im not mistaken only the shaft itself is larger, but that would mean an ever so slightly larger surface area where the flange and shaft meet. Im no engineer and dont know the exact strength difference, but from what I have seen it does not seem to be enough by any means. But as always this all depends on use, but also keep in mind sometimes shit just happens you cant plan for when offroading.

 

Not really, you are still running a 5x5 bolt pattern. i mean, if it were that simple, why not make them bigger on the D44 axle shafts?

Keep in mind that the rear housing is different than the front. The housing itself is 3.15" in diameter vs. 2.5" for the front. So, the rear is basically on par with a standard PR44 housing. The semi-float rear PR60 has the same diameter tube and 1/16" thicker wall (1/4" JK vs. 5/16" PR60). So, no meaningful gain there.

The rear ring gear is 8.8" vs. 8.5" for the front D44. It is also low pinion, vs. high pinion on the PR60 (high pinion is weaker). The actual pinion size is not that much larger in the 60 as the JK axle uses a large pinion. Yes, the ring gear is larger, but running on the coast side of the gears.

As for flanges, the guys in my area have no problem bending them on their semi-float PR60s. In fact, one bent three in less than a year. They both regret getting them.

 

^^^Actually, one of the guys I referenced above works for Jeep and just put his PR44 and semi-float PR60 up for sale. Great condition. The front is fully built with Reids, 35 spline, etc. And the rear has some upgrades. I think he is asking $8k. If you want that setup and want to save some money, let me know and I'll connect you. It is always harder to sell a rear, so I am sure he'd break the set up if you just want the rear.

 

The stock JK D44 rear is a pretty good axle when compared against a semi-60. You can add 35 spliners if you bump to an ARB, the pinion is close in size and the ring gear doesn't give up that much. With a few strengthening moves, truss,etc. you won't be far off. The money to jump to a full floater D60 starts to get nuts when you throw in a front companion 8 lug wheels, etc. Pays to do a very careful comparison before you lay down the Visa card.

Fwiw, two of our club members run Teraflex CRD60s, one in a very slick build XJ (that includes the old stock front housing from my JKUR) , the other in a built '06 LJ. Lots of trail miles, only issue so far is a very wacky failure of a flange weld that TTF took care of FOC.

 

I have been running one for the last 2.5 years. On 37's or 38" stickies, depending on where I am at.
I have had to replace the axle seals 4 times (most likely user error install actually). Not fun.
Other than that going well.

A buddy's built and not light rig (V8, 40's,blah, blah, blah) has been on semi float for years, no issues. And it gets wheeled hard.

 

Decisions decisions. It will cost me app. $2k to upgrade my existing 44 (it's an "X" model) and app. $3300.00 to get the TF CRD with 35 spline. Either way, I will be upgrading the driveshaft, so this cost is not factored.

Is the Dynbatrac semi float 60 any better than the others, such as TF and Currie Rock Jock. I know the RJ has set 80 bearings and the TF has set 20 bearings. Not sure on the Dynatrac. Many also say to stay clear of the RJ.

I have a little time before I will need to make a decision, so maybe a used semi will show up for sale!

 

I just said my friend is selling his semi PR60...

Why ask the question? You're going to buy one regardless of what people say.