Which Axles to run for 40s

Hey guys,
I just got a new XJ as payment for some work I did for a guy and Ive decided to sell my old XJ and build this one with frame stiffeners and try my hand at building a 3 link suspension for it. Rig currently has a Ford HP D44 with an ARB, 5.38, chrome moly shafts, Reid Knuckles with High steer and I believe it is sleeved (not sure on that one yet). The rear is a Waggy D44 with 5.38s and a spool, previous owner thinks there are chrome molys as well but I'm not sure so I'll have to try and figure that out. I also will have access to a set of JK Rubi D44 that will be sleeved, front C-gusseted, 4.10 gears and factory eLockers but it may be 3-6 month before I can get my hands on them. I will be putting a truss on whichever axle I choose. Goal is to run 40s and be able to do rocks and hard trails in the PNW with occasional trips to Moab. Question is which axle pairing do you think is best? I know 1 tons would be best and I've looking into Super duty axles but I don't love the width of them and I'm not sure if I want to tackle shortening them at this point. The Ford D44 and Waggy are basically ready to go with low gears so I am thinking of just running those. Think I will be breaking them every time I go crawling?

I won't comment on running 40s on 44s... so much else needs to go into the whole vehicle to run 40s, and without knowing the level of planned unibody plating (better be head to toe), if it has a cage, type of suspension set up, if it has full hydro or just hydro assist, and what's left of the body/ fenders its hard to comment on if the jeep can even handle 40 inch tires, axles aside.
That said, if it already has built 44s, why spend more coin on more 44s? The effort and money you'd have to put into the JK 44s to be equal to or greater than the current 44s seems like a waste imo? Any strength gained will be minimal at best. Truss and gusset the Cs on what ya got and save the coin for the axles and the research for something bigger.
I think 44s trussed and sleeved locked and loaded typically are best suited for 37s. There are exceptions to every rule of course.. Some will say 35s all day, higher is asking for trouble. Even the JK guys, and we know how silly they can be lmmfao

I wouldn't even consider the jk 44 as a option.

Put it together and start looking into a 14bolt for the front.

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You'll be looking at dumping a ton of money into either setup to make them reliable on 40's. You'll likely grenade Spicer 760 u-joints on the Ford 44, so going chromoly joints or RCV's will be necessary. Also, there are really no good ball joint options for the 44.

The JK Rubi 44 has the potential to be a stronger axle. The gearsets are much beefier and they use a (slightly) larger u-joint. You'd still be looking at upgrading every component on it though. Seems like it would be a great amount of money and effort for axles that are marginally better and questionable in reliability.

Run 37's on the current setup and have fun with it.

Look at bleepinjeep and dirt lifestyle. Ones a 70ish 44,9inch setup on 40s that's fairly reliable. The other is xj 44 rear and tj rubi 44 front on sticky 40s.

Driving style and being accepting of occasionally breaking of things would be the point of concern. Diff clearance would be absolutely awesome!

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Hey guys thanks for the replies. The XJ has some hacked up lift built by a senior in high school for his senior project and it's frightening to say the least so it will all be cut off. But my plan is to run the IRO full set of frame stiffeners (they seems to be the best for the money). Then I am planning on building a front 3 link long arm that runs back to a custom transmission crossmember. I am undecided on the rear suspension, it kind of depends on how much my current XJ sells for. I'd love to do a triangulated 4 link (probably just single with a slight angle on the lower links) I also want to stretch the rear a bit which would be easier I think with a link set up if I want to stretch more than a couple inches. Body has some minor fender trimmer now for the 35s that are on it but I would planning major fender trimming, probably building some kind of tub for the rear tires and looking at bumper stop options. Ultimate goal is to put on an EXO cage on it but I don't know how soon that will be able to happen in reality. I will be putting in some kind of hoop inside to run seat belts on. I am leaning towards just running the HP dana 44 and waggy axle that are in it. They are already chrome moly shafts and I was looking at RCVs and they say they are warrantied up to a 40" tire. So maybe run 39" tires like KM3 or something and obviously just watch the throttle and line I'm taking. I saw the Dirt Lifestyle, Muddy Beards and Bleepin XJ guys running 40's on front Dana 44s and they seem to work pretty well. I am also planning on running a 231 crawl box and its an auto so hopefully that will help put less stress on drivetrain from going to fast over obstacles and bouncing. I'm also throwing around the idea of building some of the bumpers and skids out of aluminum to keep the weight down but price of metals will be the determining factor on that one.

probably

MillsGarage said:

Hey guys,
I just got a new XJ as payment for some work I did for a guy and Ive decided to sell my old XJ and build this one with frame stiffeners and try my hand at building a 3 link suspension for it.

Rig currently has a Ford HP D44 with an ARB, 5.38, chrome moly shafts, Reid Knuckles with High steer and I believe it is sleeved (not sure on that one yet). The rear is a Waggy D44 with 5.38s and a spool, previous owner thinks there are chrome molys as well but I'm not sure so I'll have to try and figure that out.

I also will have access to a set of JK Rubi D44 that will be sleeved, front C-gusseted, 4.10 gears and factory eLockers but it may be 3-6 month before I can get my hands on them. I will be putting a truss on whichever axle I choose. Goal is to run 40s and be able to do rocks and hard trails in the PNW with occasional trips to Moab.

Question is which axle pairing do you think is best?
I know 1 tons would be best and I've looking into Super duty axles but I don't love the width of them and I'm not sure if I want to tackle shortening them at this point. The Ford D44 and Waggy are basically ready to go with low gears so I am thinking of just running those. Think I will be breaking them every time I go crawling?

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You can build up a 44 to run 40s. I see you mentioned RCV axles. Those are over $1,000 which is close to the price of a set of one ton axles. I know the JK axles are the newest 44s so take them if they’re free. Just remember bolt patters on all this might not line up. One tons have a lot of other upgrade costs like buying a new locker, wheels, driveshafts, brake lines, a truss, track bar, drag link and tie rod just off the top of my head.

The front axle sounds built. The rear might break an axle shaft if they aren’t chromoly. Check the rear. There is a difference between a spool and a welded diff.


Wheel the Dana 44s until shit starts breaking. Upgrade after that. The bleeping Jeep guys have a much lighter rig if you’re talking about the scorpion crawler. Buy a set of one tons of you really want to have them. You can upgrade them when you have money while you wheel yourself Jeep in its current state.


Also, make separate paragraphs for each of your thoughts. It is hard to keep track of things when you ram it all into one paragraph as if it is one idea.

Good point, I will separate in the future sorry about that.

Yeah I think I am just going to go with that axles that I already have since they are pretty much built as is.

Rear has been confirmed that it has Dutchman chrome Molys in it and the guy that gave it to me specifically said it was a spool not welded but I am going to pull the cover anyways just to confirm.

Just talked with my buddy who will building this with me before we start on his 4 door 720 overlander build and that's basically our idea. If things start to break all the time then start the 1 ton swap and build an axle at a time and that way I still have a wheeler while I'm prepping the 1 tons. Also on a side note we found that where the vehicle is on the side his garage there is a pinch point between his garage and fence that we need to make it through and we measured and 1 tons with tires will not fit, so that kinda make the decision easy.

Thank you guys for your input it has really helped me get my thoughts and ideas straight on this one.

Last question, maybe I should start a new thread for this? But anyone have an opinions on the Barnes 4wd vs IRO stiffeners for the XJ, I've read good things about the IRO's on forum's but I going to get the suspension joints from Barnes and if there really isn't much difference I figured I'd get the stiffeners there and save on the shipping.