Dana 44 FF conversion and Dana 30 swap

Hey Guys,

I'm trying to decide what the next project will be on my 1964 CJ-5A and I need some advice/opinions on a few things. I'm currently away at college and I don't have access to the Jeep until I go home. I apologize if some of my questions seem stupid, I'm going from memory with most of this stuff. F-134 with a T90-C and Dana 18.

Currently the jeep has stock axles (4.27 gears). Here's the plan...
- Herm's full floater conversion for the rear and 4.88 gears
- Dana 30 swap up front and 4.88 gears

First off, do I have a 10 or 19 spline carrier (in other words, what did CJ5s come with that year)? Assuming I have the 10 spline carrier, what will I need to convert to a 19 spline? Will any Dana 44 4.88 ring and pinion fit? I'm trying to come up with a list of stuff I'll need, worst case scenario, so I can budget accordingly.

I have a Dana 30 axle, with drum brakes, sitting in the barn at home. I'll need to get a carrier and ring/pinion for the axle since the carrier has already been donated to another Jeep project. If I'm going to do this swap, I'd prefer to do it the way I want... which means disc brakes up front. Should I just look for a newer Dana 30 that already has disc brakes or should I convert the donor axle to disc brakes? From what I can tell this swap is pretty straightforward, right?
OR
Should I just keep the 27 up front and find a set of gears for it?

Does anyone have any suggestions as to where I should search for the carriers and ring/pinion for this project? My father recommended R&P 4wd for this stuff. As previously mentioned, I plan on getting the full floater kit from Herm.

This whole axle swap/modifying thing is new to me. If my plan sucks, please let me know... I promise you won't hurt my feelings!

 

What is your reasoning behind the FF conversion? Are you just looking for added strength or looking to flat tow it?
What size tire do you plan to run?

 

'59-'70 is 19-spline.

I'm not sure you'll notice a huge difference (at least enough to offset the cost of converting) going from 4.27 to 4.88, but if that's what you want.

If you're converting to full-float out back I'd really recommend going up to 30-spline since you'll be buying new shafts anyway. To convert you'll either need new 30-spline spider gears inside your open diff, or a new 30-spline limited-slip, locker, or spool. Carrier swap is easy if you have the right tools: check backlash with dial indicator of old ring and pinion, pull bearings and shims and reinstall in same orientation on new carrier. Install ring gear, put new carrier back in and check backlash.

If you've got the Dana 30 I'd swap it in. Tighter turning, better parts availability, etc. You can get 4.27 gears for the Dana 30 to match your rear. Or, if you go 4.88s you can get those too.

 

4.88s are hard to find for the D27
as already mentioned, I'd go with the D30

 

I don't really have a legit reason for the FF conversion. I've had this jeep since I was 12, I'm 23 now, and I plan on having it the rest of my life... I guess I just want to do the conversion more than I need it. It would be convenient to be able to free wheel the hubs on the rear and tow it, but I have a flat bed trailer that I put the jeep on most of the time (unless its being pulled behind the fifth wheel).

Right now I have a 2.5" lift with 31x10.50s on it. I had 33x9.50s but it was gutless and I didn't need tires that tall to do what I do. I don't take this thing on rocks, through mud, etc BUT I do run it on the sand dunes a lot... more than 50% of its miles during the summer are running 5-6psi on the sand. I play on the hills and crawl in low range a lot. I don't molest it, but I do use it. One thing that I noticed this past summer was a popping sound coming from the hub of my current two-piece 44 when I take off under load (like soupy sand, normal take off in 1st gear low range). I'm not Nostradamus, but I'm pretty sure I'll be giving the rear end some attention sooner or later. I guess I went off on a tangent there... at least now y'all might have a better idea of where I'm coming from.

I haven't made my mind up for sure on the whole gearing thing... I'd like to get what I want and do everything at once, but I guess I could just do the FF conversion for now and do the dana 30 swap later (to avoid buying a 4.27 r&p for the dana 30 and then a different r&p later).

I feel like the it could benefit from lower gearing, that's why I was leaning towards the 4.88s. Would you suggest I go to 5.38s? Sometime down the road I will get an overdrive from Herm... maybe even this summer. I don't care about going fast, its just another upgrade I'd like to do to my baby.

I thought there was something different with the dana 44 19 spline housing vs the 30 spline housing...?? I'm no expert, that's just the impression I was under after doing some reading.

With the wider dana 30 (which is a narrow track axle), should I consider wheel spacers for the rear? I know that most vehicles have a wider stance up front, but would it look goofy since the stance is already so narrow?


Thanks for the advice, guys! Any thoughts or suggestions on this are still appreciated!!

 

you can install a full float kit on a 10/19 spline tapered axle housing.
you cannot install 1 piece flanged axles on above housings.

full float has some major benefits;
1) Ease of flat towing with locking hubs installed. (good)
2) Wheel won't fall off in case of broken axle shaft. (good)
3) Vehicle weight supported by 2 wheel bearings/spindle, not axle shaft. (good)

10/19 spline tapered axles:
1) drive shaft removal for flat towing. (recommended)
2) tire/wheel can fall off with broken hub or axle, disabling vehicle. (bad)
3) axle shaft/wheel hub support vehicle weight. (small axle bearing)

I've probably missed some other stuff .....

 

4) easier for kids to climb in back of jeep
5) coolness factor

 

The 30 spline CASE is different. That's the part the ring gear bolts to. You cannot put 10/19 spline side gears in a 30 spline open case and vice verse so if you go 30 spline (stronger) then you would need a new case and differential side gears. Powerlock limited slips are an exception to this rule.

You also need to match the case to the gear ratio you wish to run. 3.92-5.38 in a 44 takes one case, 3.73-2.54 takes another.

 

So if I got something like this...
http://www.quadratec.com/products/16100_305.htm
I could use Herm's 30 spline FF conversion for this since I'd no longer need to find a 30 spline carrier, right?

Assuming yes (and assuming I'd use the same R&P), I would need a total of:
- Locker mentioned above
- Herm's kit

I'm starting to lean towards holding off on the dana 30 swap until I can afford to get components required for the swap AND R&P for both axles. I'm just throwing ideas out there... hopefully I'm not hammering this topic to death!

 

You can use that full CASE locker and Herm's FF kit to convert your offset rear. 11" brakes or discs if you don't have them are a good upgrade as well but aren't "necessary". You will also need new bearings and seals for the differential as well. I'd recommend getting a full rebuild kit so you get the shims, seals, new ring gear bolts, etc. so you have everything you need. You are going to need that stuff when you change gears if yours are not in good shape. If you go with the 30 spline CASE and axles then your side bearings will not work anyway. I get most of my stuff from Randy's Ring and Pinion. I've had very good service from them for many, many years.

 

If your thinking of running an OD at some point then I'd forget the 4:88's and just get 5:38's. There great with an OD. They where also a stock setup so you could get some stock ones to swap in for next to nothing and clean them up an run them for cheap. I'd do that annd save for an OD.

 

Any updates?