There comes a time when the stock WJ axles no longer cut it, or you decide to invest in a smart upgrade to look even cooler in a mall parking lot. Whatever the reason, the following is a rough guide to swap ˝ ton axles into your WJ, together with illustrative pics. Besides some rudimentary tasks, all work was performed by Joe Attardo at Endless Mtn Fab (www.endlessmtnfab.com) in NE PA.
The premise behind the axle swap is a simple one - reliability on the trail. Beyond 33” tires, the D44a and LPD30 reach their limit for reliable and trouble-free wheeling. You could always throw a lot of money into beefing up the D30, but why? In the end, you still have a low pinion D30. As for the rear, despite forum legend, trussing and skidding the D44a does not make it bulletproof or solve its inherent downfall – the aluminum center section and its propensity to not like bearings or aftermarket support. Unless you have $4K+ to spend on bolt-in JK 44’s or D60’s, the following is a guide to transform your WJ’s drivetrain by way of the junkyard route, and ditch those broken cv shafts once and for all. There are several other ways to go with WJ axle swaps, but this guide applies to half-ton flavor, which is more than suitable for 35” tires in their stock form. Much of this information, however, does apply to other full width axle swaps as well.
You will need a driver’s drop for the front pumpkin.
Width with any axle swap is key. If you can get fairly close to stock WJ width, a full width donor is the way to go. However, many full width sets are much wider than the WJ. Yes, you could always narrow the axles stock width, but this gets expensive, and limits your options if a break occurs on the trail.
WJ axles are +/- 63.5” WMS. You want to source axles that are close to WMS of your WJ. The JK swap is popular since they are close at +/-66.5” WMS. Half ton Ford pickup axles from the 70’s just happen to be close enough to the WJ at +/- 66” WMS to make it work, which is only 1.25”+/- wider than stock on each side. Not bad at all, and you can “correct” this to a certain extent with wheel backspacing.
I chose a set out of a 1977 F150. A full size bronco is also an option. However, it is suggested to avoid front housings from ‘78+, as Ford went to cast radius arm mounts instead of welded. You may choose to re-tube the axles, in which case the later housings may be used. Half-ton axles from this year range will get you a HPD44 and a 9” rear (31 spline). A perfect combo, both for strength, clearance, availability of OEM parts, and huge aftermarket support for even bigger strength upgrades. In addition to huge aftermarket support and strength upgrades, the 9” has great clearance over the D44 or D60. The housings are thin, however, so trussing is a must. One potential downside of the 9" is that the pinion is a tad lower than the D44 and D60 – a pinion guard solves this vulnerability.
You should be able to pick up a set of half-ton axles for ~$300 or so. Mine came from a ’77 F150 and included Warn lockouts (yes, these axles have manual hubs). These sometimes have odd quirks – I got even luckier and scored a set where the HPD44 had ˝” axle tubes. Winner!
Specs of the HPD44: reverse rotation; 8.5" ring gear; 2.75 x 1/2" axle tubes; 30 spline axle shafts; 26 spline pinion; 5-297x joints.
Ford ˝ ton in this year range are 5x5.5. You’ll need adapters (not a fan), or new wheels. Many older trucks use 5x5.5, as well as CJ’s, I believe. Used rims can easily be found, and of course, new steelies are always available. 15” rim is a popular size, but be careful about backspacing and steering clearance -- you’ll need no more than +/-4.5” backspacing to clear steering arms. My advice is to get the wheels last, after all the steering is completed. Depending on where you live, the law may harass you about tires past the fenders – even with max backspacing, depending on your width tire, this swap may require that you invest in some fender flares or some cheap landscape edging. The tires do not stick about an obnoxious amount by any means (no more than the JK swap or stock axles with aftermarket wheels with little backspacing), but it should be a consideration.
The most common stock gearing is typically 3.55. Most likely you will have to regear. In the case of the Dana 44, you will need a new carrier in the front to run ratios higher than 3.73. As the ratio gets lower, the pinion head becomes smaller. The ring gear must become thicker to keep the teeth engaged to each other. This would be an example of why a new carrier would be needed. By moving the flange that the ring gear sits on, tooth engagement is maintained. Luckily, used carriers are readily available on craigslist or eBay, and can be found for $50 or so. The 9 inch axle has no such carrier break and relies on threaded side adjusters to position the ring gear in relation to the pinion.
9" [massive] pinion:
D44 pinion and gear (4.56):
D44 vs. D60 pinion (the D44 pinion is by no means small, but compared to the D60...):
If you swap both axles, you will lose the speedometer signal. I suppose you could machine tone rings onto the donor axles, but I personally never looked into that, nor wanted to incur that expense. The solution is to run speedo off the transfer case. This can be done if you have the 242, or 231 like me. Your 242 does not have a speedo port, so get a rear speedo housing that does and swap it. Find the right speedo gear to match your gearing/tire size, and you’re set. Courtesy of Mallcrawlin, here is a link explaining the general concept of wiring your new speedo gear (starting at post #5): [MC link]. There are a few other links out there (MtnMarc has some good info in his build thread), but be careful -- Chrysler used different wire colors for different model years, so you need to verify with the FSM or by multimeter which are the applicable wires. What I'm saying is, disregard the wire colors that others have referenced because unfortunately, its not that simple.
At some point, I may make a separate thread but for now a few tips: you can use any of the four speedo sensors to accomplish this task, but most use the left rear since it makes routing the wires easier and neater; the speed sensor wire at the wheel has 2 wires -- 12v supply and 5v signal -- figure out which is which with a multimeter or correct year FSM, and splice into your "new" speedo sensor accordingly (your new speed sensor has 3 wires (power (12v), ground (middle wire), and signal (5v)); once the new sensor is spliced into the existing rear sensor, you move up to the front at the ABS harness/CAB -- using your correct year FSM, find the wires at the ABS harness for vehicle speed sensor (VSS) and the left rear speed sensor signal (assuming you used the left rear wheel sensor), splice these two wires together at the harness BEFORE the wires enter the plug (leave the other halves of the vss wire and left speed signal wires cut and unattached at the plug); turn key to "on" position and verify you have speed by turning by hand the speedo gear; if you did everything correctly, the speedo will move in relation to your spinning of the gear; solder the wires, shrink wrap, etc and otherwise button everything else back up. Note: you need to have the ABS plug connected in order to complete circuitry.
You will lose ABS if you swap both axles. Solution = pull the ABS fuse and don’t be a pu55y. Bye bye ABS pump and wires.
For the most part, 70’s axles will have front disc brakes and rear drums. There are several kits (aftermarket and junkyard sourced) to convert the rear to disc. I will run rear drums for now. If you run rear drums, you will have to install the correct proportioning valve for the brake booster. A vehicle with rear discs requires more fluid than one with drums and would send too much fluid to the back wheel cylinders. As an interesting note, one should not automatically assume disc brakes will stop better than drums. In terms of sheer stopping power, drums have the advantage. However, by the time you factor in brake fade, complexity of parts, cost, etc, disc brakes do present an appealing option.
The e-brake cables from the donor axle can be reused. Shorten and then simply hook back up to the bracket that is located underneath the rear seat.
To plumb everything in, I picked up a proportioning valve made by Wildwood. This is perfect for front disc/rear drum set-ups. A simple twist of the valve will give you more/less rear brake. Existing lines fit in to the new prop valve. You will have to swap fittings supplied with the kit for the new prop valve connections due to Jeep using metric fittings. The front electrical plug is not used -- you can either let it go or swap out for a plug fitting. The existing lines will have to be shortened, bent, etc. to properly fit the new valve. We fabbed a simple bracket for the new prop valve that bolts to the master cylinder studs. Here's a pic:
Pull the ABS wires and e-brake cables. These are accessed under the rear seat. Both ABS cables have pigtails under the carpet, and the e-brake cables are right there under the carpet as well. Rear ABS/E-brake cables removed:
All brackets and truss constructed out of 3/16” steel with gussets and braces in appropriate places.
I run Clayton’s 4 link rear set-up. Honestly, it probably would have been much easier to fabricate brackets building double triangulated 4 link from scratch given Clayton’s constraints and mounting points [warning: do not put Clayton’s kit into a link calculator – you may be disappointed]. That said, Endless Mtn Fab’s brackets improve on the rear Clayton’s geometry to achieve much a more neutral suspension. The corrected geometry will make a world of difference to both off and on road handling and performance. Clayton designed a suspension with simplicity for the end user in mind and had limitations to consider. Luckily, it can be fixed.
The new setup compliments the existing 4-link, with 3-levels of adjustment to fine-tune handling/function to your preference. The upper arms have been spread wider to help counter the shorter than desired arm length. The rear lowers are now triangulated by a very minor amount in order to create a little more stability. Coil buckets, swaybar mounts, and shock mounts are incorporated into the truss. Bumptops are stock TJ cups, with WJ rubbers machined to fit the cups. Control arm mounts, shock mounts and sway bar mounts are located higher up on the axle, which even more takes advantage of the added clearance of the 9” over the D44/D60. Pinion angle is set for optimum angle with the SYE.
The rear truss is over-the-pumpkin, tube to tube for max strength, with incorporation of a back truss. I would like to think it’s pretty safe to say that this axle will not bend. Ever.
I was lucky enough to score a donor HPD44 that for whatever reason, has ˝” tubes. For this reason, a truss was not really necessary due to the thickness, but you still would need to fabricate a bridge to incorporate the upper control arm mounts, etc.., so why not make it bulletproof? It would not hurt to weld the tubes to the centersection while everything is being made. Doing so reduces the chance of spinning a tube.
The axleshafts machined to accept full circle clips over the traditional c-clips. Although it is slightly more irritating to replace, the full clips offer a cheap, but effective strength upgrade.
Clayton’s front suspension is commonly termed a “radius arm” design. Another name for this style of suspension is “Y link”. For some individuals, a radius arm suspension is a compromise. There are numerous posts and articles online about these arms, so I won’t cover them here. There isn’t much that can be done to improve on the geometry of these arms, however some minor tweeks to the mounting points help push the suspension in a more neutral direction. A center limiting strap will help prevent unloading. When the money tree recuperates, my intention is to convert to a 3 link front.
9" all cleaned up (note the bar through the center section, tube-to-tube to check for any smiling or frowning):
9" center section with pucks and straightening bar:
Beginning work on the 9" truss:
Another truss pic:
Reinforcement to the pumpkin with 3/16" steel plate (good pic of 3rd member):
Action shot (note plate on top):
More progress on 9" (rear shot):
More progress on 9" (front shot: upper/lower brackets shown - note how high lower brackets are tucked up on the tube. Also, uppers have 3 mounting heights to dial in roll center/antisquat to some degree):
You have several mounting options here and each style (i.e. inverted T, inverted Y, crossover) has its own pros & cons. I am going to try a high-steer inverted Y style of steering. Inverted Y is stock on the XJ & TJ (and others). It is less prone to death wobble even with worn parts due to the fact that the wheels are not directly linked by the tie rod - the draglink attaches to the knuckle, and the tie rod attaches to the draglink. Some prefer the inverted T, but I'd rather not deal with the inherent dead spot. Last is crossover, which is stock WJ style. High-steer crossover or high-steer inverted Y appear the best two choices to me. Whichever is selected, design is obviously crucial.
Every vehicle responds differently, so don’t be surprised if you have to make changes. Don’t forget to swap your pitman arm either. The arm must match the ratio created by the steering knuckle. Generally, the full size trucks have longer arms, so it should just be a matter of finding the correct amount of drop to match your steering & track bar angles, plane, and length, in addition to lift height. For my application, I sourced a DPA from Superlift designed for a Waggy (Part No. 1104).
Knuckle drilled and insert welded in for high steer:
This is roughly what the steering will look like. Tie rod is 46"! Designed for max clearance and matching lengths/pivot points/plane of trackbar and draglink to eliminate bumpsteer (Note: no trackbar in this pic and using stock F150 rods for mock-up):
New draglink installed w/rod ends and drop pitman arm. Multiple views shown at ride height. Draglink angle is ~8*.
Caster is a somewhat subjective feel for the driver. The Clayton upper arms offer adjustment that allow you to strike a balance between caster & driveline angle. If you are unable to find a happy medium, offset balljoints maybe provide that little extra adjustment needed. Otherwise, a cut/turn of the knuckles may provide the ultimate solution.
Breather installed in both front/rear tubes.
Ported for ARB’s.
Upper swaybar mounts at the unibody were cracked. Plates welded in (perimeter and several plug welds). We are experimenting with used JKS swaybar links to alleviate sideways stress imparted by the rear bar. No provisions for disconnecting were incorporated due to stability concerns when flexed out.
Limit straps are being employed to prevent over-extension of the shocks and/or breakage of mounts. As mentioned earlier, the front is also receiving a single, center strap to minimize unloading.
Kit fabricated with gas tank/skid in its current location. Purposefully done this way so that bracket kit could be sold to those with or without a tank tuck.
Driveshaft - depending on your set-up, your driveshafts may have to be modified. In my case, the rear driveshaft was slightly short because of the short 9 inch pinion shaft combined with the lower centerline. A longer stub was sourced from JE Reel driveshafts. A conversion joint was included ( Spicer 1310 to 1330). The front Dana 44 Is a High Pinion/Reverse spiral design that puts the pinion above the axle centerline. The Dana 44 pinion is also longer than the factory Dana 30 in our WJs. The combination of the high pinion (reduced driveshaft angle) and long pinion necessitates a shortening of the front driveshaft.
Unfortunately, this is not a swap that can be done without welding skills, fabrication skills, and a lot of know-how. I could not have navigated through this endeavor without the expertise of Joe at Endless Mtn Fab (www.endlessmtnfab.com). His work is amazing. While Joe has done countless axle swaps, this is the first of this type on a WJ. Lucky for you, the bracket kits to do this swap will now be available. You will now be able to source all the parts yourself fairly inexpensively, buy the soon-to-be-released bracket kits from Endless Mtn Fab, and then pay a buddy to weld them in. As simple as that.
The half ton swaps in general are a significant upgrade from the factory parts. However, it does not mean that everything is bulletproof. The weak point of the HPD44 is the axle shafts, which could set a chain reaction through the ball joints for a pretty bad day on the trail -- obviously, chromo's helps greatly to solve this deficiency. The 297 joints of the 44 aren't great either, but with chromos and some HD joints, you should be set. Even in its "stock" form, with some common sense, the half ton parts should be able to survive turning 35 inch tires, locked. The 44/9inch combo is well supported by the aftermarket community and make 37s a distinct possibility. Me? I’ll stick with 35s.....for now.
Feel free to ask any questions, or request a certain pic not included above.