Spline Upgrade

I am in the process of going to 3.73 gears in my 66 cj5 but with my old D44, taking with Herm I need a new carrier from 5.38. My question I guess is do I have to pull axle to find out my spline count Herm mentioned I should have a 19 and that they don’t make 10 spline axle shaft. But when I asked about the carrier he said 10 or 19? Am I losing my mind or am I missing something? Can I pull the diff cover off to see spline count or can k upgrade to 19 or 30 spline. Want to get full floater kit but changing gears and changing carrier and if I get the FF kit, can’t I just get all that in 30 spline?

 

If it's a stock '66, it's 19 spline. Yes, you have to pull a shaft to see the count. I would stick with 19 for the FF, the spindle gets pretty thin with the 30. 19 spline is well within the strength of the other Dana 44 components, if you stay with 33" tires or smaller.

 

10 spline was before the CJ5, it is possible to have a 10 spline but it should be 19 spline. 30 spline allows for more locker choices but it's lipstick on a pig. These things aren't the greatest on road no matter what and the tubes are lighter than other 44's so unless you play hard, or you are wealthier than most, or you make money with your jeep (youtube channel, plow snow, agriculture) i don't see a need for 30 spline since it adds up quickly.

 

Well originally I believe the jeep was a 62 m38a1 with C channel frame. So if it’s a 10 spline can I upgrade to 19 with all of Herms FF kit and new gears and new carrier? Or is it what it is I have a v6 in and thinking of V8 with 4 speed for more cruising around and some highway. But before that I want to change my gears and I know OD is not good for long duration on highway speed. I mean what else would I need to change to 19 spline I’d I have a 10 in it?

 

I put a 30 spline power lock case in my D44 that originally had 19 spline axles in it when I made my full float axle.
http://www.earlycj5.com/xf_cj5/index.php?threads/112223/
If you want anything modern for lockers or whatever, you're going to want something with 30 spline axles.

 

19 involute became the military and cj standard in late 1956 model year and it coincided with Powr Lok developement.
So it’s inlikely to have the early 10 milled spline axle shafts.
You don’t change the “carrier” because the axle housing “carrier section” is the portion of the axle weldment assembly that surrounds the differential unit.
A 4 speed will not increase hiway speed. And you are mistaken because an OD is specifically meant for hiway operation. Plus it works equally well as a gear splitter.
Unless you are slow crawling under great torque or producing high HP the 19 involute axle assembly will be quite dependable.

 

I don't remember Chris' spindle setup, but I have seen them get kind of thin with 30 spline. That was my only reason for the 19 spline vote. It's been a while since I bought anything 19 spline, and I never really look at anything besides a Detroit Locker, and I think you can still get them in 19. Also, my experience, not having broken a 19 shaft in 15 years of Rubicons on 33's, I think they are fine. (I did carry spares all those years).

 

Another that thinks 19 spline will likely suffice. That said, it does limit your traction device options. And be aware that Herm's 30 spline full float kit does allow you access to all the 30 spline traction devices but the actual axle shafts are probably not as strong as 19 spline full float shafts due to the design. Read this thread:
https://www.thecj2apage.com/forums/sanity-check-d44-full-floater_topic46710.html