I'm expecting to jump to 37's in a year or two. I'd like to have an axle built to take 37's or larger, Atlas 4 speed w/2.7:1, 4.3:1 & 11.6:1 low ratio, ZF 5 speed, 4.56 gears, and eventually a 351 stroked to 383 or 400.

A while ago I read about a company who makes a kit to fit a D50 ring & pinion into a HPD44, known as a Jana 54. Its a complicated install, but gives you a larger ring gear, in a relatively light D44 housing. It only adds $150 in parts, plus grinding & other labor to set the gear up. Although the D50 has a larger gear, it has the same pinion spline diameter as a D44.

I see 2 options for a strong HPD44, neither is straight forward:

Jana 54, with RCV or other high end axles w/expensive u-joints.

or

Jana 654, same ring & pinion, but remove D44 knuckes, replace with D60 knuckles, brakes, and axle shafts. There is a 35 spline ARB locker that fits the D44, that makes all this fit together.

What I realized, after spending some time on the Mr N's sites looking at axle lengths, is this was more complicated that I expected (and I didn't think it would be easy). The inner shafts of a HPD44 and a HPD60 are not the same lengths.

So the D60 inner knuckle C's would have to cut & machined/sleeved to fit a D44 housing, also the length of the axle tubes would have to be adjusted to match the axle D60 axle length & jigged for caster.

It dawned on my that this was far above my knowledge, skill, and equipment levels. To get this kind of job done, I think it would be best to leave it to a company like Crawler Tech, who are set up to build axles correctly. The point of this is to build a bullet proof axle. I'm afraid, if I do it myself, I'd end up with blowed up bearings, u-joints, ring & pinons, or worse.

I've been thinking about the 654 option for quite some time. By some luck, I recently sourced a bent 95 F350 D60 axle complete. It was way cheaper than trying to source all the parts separate. I originally expected to cut the knuckles off & use it for a Jana 654.


Option #3 would be to repair or replace the damaged D60 housing, and run a D60.

PROS: You get the full strength of the D60 axle, including ring & pinon. With no special gear kit or extra set up cost/time.

CONS: Size & weight.

I'm guessing the cost of Crawler Tech building a 654 housing vs fixing my D60 is about the same. Or, I've found some D60 housings on car-part for about $400. I'd still be in the D60 less than I've found on CL or Ebay.

I already have a D70 rear axle, so I'm pretty much not choosing option #1, due to lug patttern. I'm going to have to buy 17" rims, to jump to 37" tires. Dodge has used 17" rims with the old 8x6.5" lug pattern until recently, and I've watched many sets of used rims cross CL between $100-$200. Less than finding 5x5.5" 17" rims.

So, is it worth fussing with a complicated, custom Jana 654 axle. Or just fix the D60 and run it.

If you didn't already have a D70 rear.
If you didn't plan on at least 37 inch tires.
Then I would consider the hybrid axles.

But since you do have the D70 and are planning 37's or bigger then the D60 is probably the best choice.
I don't see where you would gain enough with the others to justify the expense.

More common + less work = less expensive.

I hate the ground clearance of a 60 and that is the only reason I will build a 609 for my front end when/if I start breaking the D44. My D44 is built with good parts and has not let me down in a long time now. Yukon spool, yukon gears and yukon Hardcore axles with yukon gold joints have been in there for a few years now with no failures.

However, since you're already committed to the rock anchor of the D70, you may as well build the D60 once and be done.

I agree with the above. I'd just go D60 now and be done with it. Have you called crawler tech to see what the cost is on either axle? If it's too much just remember you can some 3/4 outers on the HP44 now to match the rear. If you do keep the 44 I'd go selectable locker up front. And also remember that if it starts to dig get out of it.

FWIW I still rock the stock shafts in my 79 on 37's. That's with a healthy 460 too. But it's open in the front and im easy on the throttle.

Thanks guys. I know I could make the D44 work, probably for a while. I don't have much real hard wheeling under my belt. And I do have a history of using the skinny pedal. I haven't broken much/anything, but don't want to start. I know I'm giving up weight & clearance. But I also know I might not stop at 37's. And a D60/70 combo wouldn't need upgraded again, probably. I'd like the hybrid axle, and I'm keeping my options open. At one time, I was considering keeping the 9" in back, but that would require another "kit" to make the D60 stuff 5 on 5.5" lugs. There are no 8x 6.5" axles for the 9". I've also recently read the ARB for a 35 spline 9" is poorly designed.

I contacted Crawler Tech, regarding straightening the axle. He wouldn't even give me a ball park estimate for repairing the axle, without bringing it to him. I'll do that this summer, possibly. I'll ask about the hybrid costs then. But due to recent economic issues, I believe this project has been pushed back to at least the winter of 2016/17.

Rob, I was thinking what you were, about swapping to the D70 first. But without either regearing the D70 or the D44, they won't match. So I will probably do it all at once, even if I have to buy a used set of 33's to get through next summer.

So another concern, I forgot when typing last night, would be the issue of the weak link in the system. Jantz engineering states by putting stronger axles in a D44, the ring gear becomes the weak link. But, by putting RCV, Yukon Hardcore, or D60 axles, on a D50 pinion (with the same diameter as a D44), isn't the Jana54 just moving that breaking point to the pinion? If I had to choose, I'd like the system's fuse to be in an axle ujoint or driveshaft u-joint, not the ring & pinon.

This all started, because I realized a D50 gear set + Jana kit + RCV/Yukon axles = a lot of money. I was trying to do this sorta cheap, and 'off the shelf/junk yard', as replacement parts would be more readily available. Or i might have just done the easier route.

I should say I'm not married to any idea at this point. I could sell everything I have and probably come out even, or ahead. I'm flexible right now. The parts I have have fallen into my lap, so to speak

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I'd run the straight Dana 44 with 37's and see if you wind up breaking parts. A decently built 44 should be able to handle that size in a rig with reasonable horsepower and weight. I've done some reading on the Jana 54, but for the cost and hassle I'd go 609 and call it a day. Lower weight, similar clearance to a 44, and the ability to drop the third to work on the gears, but with near Dana 60 strength.

I would run a hp44 front as it corrects a ton of issues and has a 1/2 tube. Put on knuckles , Yukon axles and joints , locker and a good steering setup. Match the rear width with a 9" housing 31-35 spline and its beef steak

I still agree of running the HP44 and 9in. With some good shafts they are hard to be beat in a light weight rig. Ya sure a d60 is stronger and less chance of breakage but you really gotta ask yourself what kinda wheelin you are gonna be doing. You gonna go 40's and run coyote canyon? or Montrose? or just stick with whats around Colorado? with 37's on a d44 I do believe it can survive for most people's wheelin around here. Just gotta drive with your brain not right foot. I'd just keep a selectable up front.

Thanks for the responses. Got me thinking.

I viewed the D44 with 60 axles as a 'cheap, but complicated' alternative to the Yukon/RCV axle. I only ditched the idea of running the 9" because the lug pattern didn't match. Maybe I need to look into running 5 on 5.5" on the D60 hubs.

Trei, what does it take to switch from 8x6.5 to 5x5.5?

Why a 609 vs the 654? I thought the "reverse rotation" gear was a better choice for a front end, than the regular rotation 9" gear.

FYI I am running a early bronco big bearing 9" in back with yukon 31 spline axles, yukon spool and yukon 5.13s. Up front I'm running the stock D44 housing with yukon spool, yukon 5.13s, yukon hard core axles with gold joints, stock 79 ford knuckles and very heavy duty steering. I've run carnage canyon BV, Penrose, Pritchett Canyon, helldorado, green day, bandimere rocks and a ton of other hard trails on 37s with absolutely no breakage. Never saw a need in bigger tires as I was keeping up, and doing better than most rigs with bigger tires. 37s are plenty for me and my bronco is just flat out not breaking. With a full bodied bronco it would likely take on a lot of damage on the trails I've listed with any tire size. I'd stick with a properly built 9" and D44 with 37s if I were you.

Thanks JD, Jason, & Trei!

Its VERY reassuring to know the D44/9" will hold up to 37"s+. If you guys are making it work, I know I can. Its also good to know 37's are more than adequate. Reliability is key, maybe I jumped off the deep end considering 1 ton stuff. I really only considered the 1 ton rear to match the lug pattern on the D60 stuff. I wish someone was making 9" axles with 8x6.5" lugs.

I'm running 79 Bronco axles now, so my 9" is a 31 spline.

Because of the info I've got from this thread, I'll reevaluate my choices.

Seems like I should sell the D70.

For my front end,
I need to decide if the D50 ring & pinon is worth it. Also if I should invest the time & money in putting the D60 stuff into a D44, or if I should just drop the $ on RCVs or Yukon axle shafts . I'll contact Crawler Tech and see how much they would charge for the axle housing work. I also need to figure how much it costs to run 5 lug on a D60 hub. If the cost of the 5 lug conversion+ housing work is too much, then I'll sell off the D60 stuff, and just buy a set of axles for the 44. Its sort of seeming like the work to run the 60 stuff, just doesn't add up.

For the rear, I am leaning towards just upgrading to chromoly axle shafts vs changing everything for 35 splines.

I'm not done driving my Bronco on the street & in the snow, so selectable lockers seem like the best choice.

The nice thing about keeping it D44/9", I can upgrade my gears, sooner than later.

Keep throwing ideas out there, I'm going to keep looking into the Jana 54 & the hybrid D60/44 options & I'll keep posting up as I learn stuff.

Is the D60 a kingpin or ball joint axle?

Ball joint. Its from a 95ish truck, has the bolt on calipers, not the sliding calipers.

Chad, here's my $.02:

1. With the low/low crawl ratio you will have with that thing, and the fact that it is a manual tranny, any accidental blip of the throttle will likely destroy a front axle shaft with 37" tires. Fact: manual trannys are harder on components than autos due to driveline shock and the increased direct application of the torque multiplication.

2. No way would I put a D70 in the back, a Sterling is a better choice and there's no case break like a D60. If I needed a boat anchor like that I would go with a 14bolt, so you have the extra pinion bearing like a 9". Personally, I run a 35 spline ARB in a TruHi9 with the 2nd load bolt in the BBEB, a Sterling with ARB in the BBB and a spooled 35 spline 9" in the buggy (with redrillled D60 hubs, 35 spline inner/outer and drive slugs in front).

3. Axles don't need trusses unless you are jumping, or to enable suspension component mounting points. And if you're jumping stuff, you need to fix a whole lot of other components to stand up to the abuse, and do them first.

4. Converting to 5x5.5 on a D60 outer setup is easy, redrill the hub/rotor and machine down the outer diameter of the D60 hub so your wheel fits over it (IIRC down to 4.1"??). A competent machine shop can do that for $100/pair.

5. Yes, the D60 inner shaft lengths are not stock, no big deal, pick up some used D60 shafts and have them cut down/resplined to the right length, IIRC Moser charges $75/pair to do that, plus your shipping. You can probably find a local place to do that for a ballpark similar price. Or order new ones the length you need. Outers need to match the external components based off what you decide to run, redrilled SD unit bearings, vs 30/35 spline, etc...

6. Lighter weight means less stress on the Bronco as a whole. Lighter tire/wheel package equates to less stress, .......... It's a total package. I can do stuff with the buggy because it weights like 2800# and almost never exceeds the traction threshold of the tires (Krawler Reds help...).

7. I will be building a 654 in the very near future, I have most of the parts assembled, but it's hard to get stuff done when you work 80+ hours a week and travel. Much better ground clearance, etc... and I can probably get it done for less than buying a D60. BTW the weather in San Diego is beautiful...

My plan is to put the parts in a '77 F250 RCD44 I have, J54 kit, add the 35 spline D44 ARB, cut down stock D60 shafts, redrilled Superduty unit bearings/rotors, D60 balljoint inner/outer Cs. I still need to solve the brake calipers, I believe that's just ordering the right carrier to bolt on the SD outer knuckles (like the '97 F350 D60) and figure out my locking hub/stub axle.
HTH, Joe

5 5.5 on a Dana 60 is becoming harder as blackbirds custom is no longer making hubs. There are a few other companies do it but it's few and far on ford hubs. The hubs can be drilled buy a machine shop too

Thanks for all the info.

I didn't realize there was that much weight/clearance difference between 1-ton rears. I did some reading on the D70 before purchase, but obviously didn't read enough.

I have a hard time wrapping my head around the process of sizing the axle housing to axle shaft length. Its something very far from anything I've ever done.

Crawler Tech has been no help. I emailed him today and asked to 'ballpark' assembling a 44/60 housing. He said "it was cost prohibitive and D60 shafts break D44 gears." I've sent 2 very short, very to the point requests for estimates/ballpark prices (not quotes), so I could budget my build. I explained I live in Gunnison, and don't get to Denver often, but want to get a ball rolling. He wouldn't give me any estimates at all, not to fix my D60 or put a hybrid axle housing together. I don't know if I'm talking about $100 or $1000. Not helpful, and probably will not do business with him, disappointing. Honestly, it doesn't feel like he wants my business.

You do have to understand josh does a lot of 14bolt stuff and that's his wheel house. I will say a hp 44 will be all you need for a 37" tire rig. Throw some rcv axles and a good locker and it's pretty strong

Josh may just not be a great communicator over email. I've swung by the shop a number of times and he's always taken time to answer my questions and offer advice despite my not being a significant customer. He also faced my diff cover for free and offered to charge my shocks for free, despite my offering to pay. My axle either came to me a little warped or got warped by my welding on it and I talked to him about straightening it. His advice was to build it, see how it aligned, then bring the housing in if it couldn't be aligned without problems. His thinking was that most older axles were a little bent and ran without problems, so it was worth it to see how it worked before investing the extra money. I'll swing by next time I'm in the area and ask about costs to get it straightened, as he's one of the few places I'd trust to do it.

I know I'll be over geared.

4.56 seems like the least I can run with 37's & my current 302. I'll still be using the ZF as a 4 speed. I can't hope to use OD, unless I go 4.88 or more. I'm planning on a bigger motor that will be able use the OD. I know you run a 4.1 gear, and I wanted to, but there is no way my little 302 would turn the tires over. They don't make a 4.30 gear for the D50. If I don't do a Jana 54 gear, I might consider the 4.30.

I don't know how much I'll use the 11.6:1. You probably know better. I really wanted a 4:1 or 5:1 low, but didn't want to loose the moderate low for general trail running. The 4 speed Atlas gives me both, plus the ridiculous 11.6:1 as a bonus.

Ooops I'm all wrong the D70 doesn't come in 4.3.

HPD44 doesnt' come in 4.3, but D50 does.

My opinion on the gearing,

the 11:1 is gonna be useless for how you have used the truck. I'd also go deeper in the diffs. atleast 4.88/5.13's. Even with a heathy motor 4.10's are to tall for 37's. 4.56 is a little better but not quite enough. (im talkin highway/city driving). example: although my 79 is a lot heavier than an eb, I had put 37's on it with 4.10's. It was great around town on the highway. would cruise 65-70 at 2600rpm. But even with a 460 makin ~350hp/550tq it turned out to be worthless driving in the mountains. It was not in the powerband so was constantly having to drop into second and get the rpm up. I have since regeared to 4.88's and was a night and day difference. Now I could cruise all day in the hills at 55-60 and have plenty left over. That's where the flat highway driving suffers. I now don't run it much above 55-60(2900-3000rpm) on the highway. Wishing I could have overdrive in it now for the city driving.

All the talk has been about low range wheeling and such. But since you mentioned street driving you also have to take that into consideration. when the t case is in 1:1 you will need help in the axles to turn those tires. Just food for thought.

Rob,

Thanks for the info.

From the calculator I was using, the 4.56 gears would run roughly 2700 rpm at 65 mph, in 4th gear. I had hoped that would be ok, but honestly have no idea. Its about 300 rpm higher than I'm running at 65 right now.

The same gears would run about 2100 rpm in 5th gear. I knew I wouldn't be using 5th until I put a bigger motor in.

A couple guys around here led me to believe their trucks were running ok with 4.10s & 351s. & a ZF (JD & aaah1).

Its even harder to predict the off the line power. I used the crawl ratio calculator (2nd gear, not the granny, 1:1 t-case). The NP435, 3.50 gears = 12 crawl ratio. The ZF, 4.56 gears= 13 crawl. I was hoping that was enough.


I think I'll give this a chance to play out. Justin is putting 4.56s in his truck. I guess he'll be my guinea pig.

I am thinking I'll probably re-gear when I jump to 37's as well. I'll probably try what I have for a while first... I don't blame you there. What's interesting is that AA doesn't even offer my gearsets anymore. You have the 1 choice for the 4spd, as I did then, but it's 2.72/4.26 where mine is 2.72/3.6 something.

You'd be amazed at how much you will use low/low on the very technical stuff. It's fun!

They do offer a case that ends up with a 10.?:1. At least it was on the web site last year when I was buying.

I would like to keep the axle gears as high (numerically low) as possible. Since my t-case gears are outrageous, I don't have to worry about low gears, I'll always have enough.

I was really happy running 4.10 with 35's. I'd planned to go 4.88, but got a screaming deal on 4.56, and it's enough of a drop that I think I'll like it. The 4.10s were a great compromise between highway rpms and off road lowness. I've had a few times that I would have liked lower, but a lower t-case ratio will easily take care of that. The 6.72 in the NP435 helps make up for the higher axle ratio. I do have to downshift on long steep grades, but the added torque of a 351w will make the mountains a little more fun, and driving it around town is better with the higher gears. When I looked at the gear calculator to see how an overdrive would affect things, the OD of a ZF5 would have me running around 2500 rpm at higher highway speeds-perfect for running up and down I-25 given a healthy engine with a torquey cam.

As always, it really comes down to your individual application.

Hope you are right. That is about how I figured it.

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