Axle swap in a 78cj5

[SD78CJ5]

Hey guys!

I have a 78 CJ5 , l6, T-18 tranny (T-18 -1b is the stamp). I haven't confirmed the Transfer Case . AMC20 rear, Dana 30 front.

Backstory

I live in the flat lands of South Dakota, so my main and practically only wheeling is mud and dirt hills, although rocks do tend to stick up in pastures. 90%+ of my rigs time is daily driving. I run 33" tires but 35s or 37s may be in my future depending on how this goes.

I rebuilt my AMC20 at 16, and well... didn't know enough. It works nicely but because the lash wasn't set correctly my pinion seal leaks. It has solid 1 piece axles (if I remember right I used alloy usa). I also might have a plan for this axle in something else.
The Dana 30 front is more or less shelled from when I limped around in 4x4 when the rear had 2 piece axles that failed. At least it will need a new ring/pinion/rebuild kit.

The leaf springs also go under the axles, and the PO used a rancho add a leaf and added...many... leafs. My suspension is practically solid, and to add to that the bottom leaf sticks straight out and they love to carry weeds/bash into rocks.

I'm looking into full length axles. I want this because following another vehicle is pretty hard with the shorter axles as I'm bouncing from wheel trail to wheel trail. This is mostly an issue when going through snow. I also would like to go wider to give me a more stable stance. I currently have 6" fender flairs and I'd like to tuck the wheels between them (73" edge to edge...this would include wheels/tires installed).

My current springs that sit on top of the added leafs are in bad shape (bent, cracked, broken, military wraps coming undone). I don't want to sit up higher than needed to fit the 33/35 inch tires, I also want to go SOA. I'm assuming just about any spring is going to be more comfortable than my current set-up but it would be ideal to get the best ride quality springs.

Getting to it now,

What I want (order of importance):

A more comfortable ride.

SOA and high steer. See "rocks sticking up out of pasture"

Wider axles that when wheels/tires are mounted, measure 73" from the outside of one tire to the outside of the other. I'm sure rim backspacing gives us a little play here. 12.5 or 13.5" wide tires are the most I run.

Stronger axles. I plan on getting lockers front/rear at some point, and the most power I'd give them is a mild 350...but keeping the i6 for now.

What I've researched:
Waggy springs/axles or dana 60s from a rare gem of a ford.

I was pretty set on the dana 60 option but am now leaning towards dana 44s as I don't really beat my axles up rock climbing, and the i6 isn't dumping loads of power. I also read the dana 60s weigh a ton, and the 44s have more ground clearance?

I went to school for mechanical engineering and was a welder for a couple years, as well as hobby welding for most of my life, so I'm not too bad off here. There are loads of junkyards/salvage yards in the area and axles probably won't cost me much due to a low demand.
What's my best option here? Buy a ?year waggy and rob parts?

I appreciate your response!

 

[Old Dog]

For soa I would look at a chevy axle for the front as it's already set-up for soa.
You will need to cut the long side down about 4" and change the hubs
to fords to get your 5x5.5 bolt pattern back. The chevy will also get you
at least one flat top knuckle maybe both depending on what year it is.

You could also change the rear to a 6 lug axle and buy new wheels.

 

[SD78CJ5]

Thanks for the response.

I'm not opposed to getting different rims, and I need new tires anyways. I can't stress enough how I don't want anything hanging down anymore, pretty much axles only.

I've just recently stumbled upon the waggy swap, I need to see if they are SOA capable (I'm sure just about anything can be MADE to do whatever it is I want, but less work is more time on the road!)

I don't really want to cut axles down, as this project is going to be pretty consuming as it is. I wouldn't say I'm against it, and on another forum chopping the chevy axle was mentioned, but with the availability in my area for just about anything I'd have to think there's something pretty darn close to what I need.

 

[Kane]

For 33 inch tires the Dana 44 are the best choice. With full width axles you will need to out board your front leaf springs and the rear will need the spring pads on the axles cut and relocated. To be honest it might look a little ridiculous with full widths and those size tires on a soa swap but it will be flexy for sure. Don't forget the turning radius will suffer a bit as well if that is important to you.

 

[Posi]

For soa I would look at a chevy axle for the front as it's already set-up for soa.
You will need to cut the long side down about 4" and change the hubs
to fords to get your 5x5.5 bolt pattern back. The chevy will also get you
at least one flat top knuckle maybe both depending on what year it is.

^^ for the front, and 60-2 for the rear. One of the best swap-in for the rear IMO. Semi float 35 spline just need to cut one side, plus it's already 5 5x5 bolt pattern. You can find them in 3/4 J-trucks.

 

[SD78CJ5]

For 33 inch tires the Dana 44 are the best choice. With full width axles you will need to out board your front leaf springs and the rear will need the spring pads on the axles cut and relocated. To be honest it might look a little ridiculous with full widths and those size tires on a soa swap but it will be flexy for sure. Don't forget the turning radius will suffer a bit as well if that is important to you.

As long as it's not like trying to turn a quad cab long box truck I'm not too worried about it. Any ideas on how much it suffers or just common knowledge about making it larger?

What sized tires go best with a stock height spring SOA setup?

 

[Kane]

This is only my opinion but an soa on a CJ5 with 35s is too big. Now my buddy did it and ran hells revenge in moab no problem and it rode pretty nicely but i did not like how it felt when climbing hills. I have owned my 5 for 23 years so i know the handling quirk pretty well. For me personally 3 inch plus 1 inch body and 33s is max height. On a CJ7 or 8 then soa is fine.

To your question the 35s did look right with his soa on the 5.

 

[SD78CJ5]

This is only my opinion but an soa on a CJ5 with 35s is too big. Now my buddy did it and ran hells revenge in moab no problem and it rode pretty nicely but i did not like how it felt when climbing hills. I have owned my 5 for 23 years so i know the handling quirk pretty well. For me personally 3 inch plus 1 inch body and 33s is max height. On a CJ7 or 8 then soa is fine.

To your question the 35s did look right with his soa on the 5.

Thanks. I wonder if I can get a set of springs that are lower than stock springs without causing issues. Around 4" lift is all I wanna do with it, as another reason for full width is added stability. I'm not sure how much lift it currently has as the PO added a couple springs. 35" tires are also as large as I want to go, being a daily driver.

 

[HackFabrication]

If you've got a bottom leaf that is catching on stuff, someone probably installed an add-a-leaf to beef up the stock suspension. Possibly to add a snow plow. The aftermarket lift kits, to my knowledge, do no have that bottom straight spring. My 2.5" BDS lift does not:



You can get a better quality ride by doing a YJ spring conversion. Reverse the front shackles and that will prevent some of the 'jarring'. Spring Over Axle conversions, are expensive, to do 'right'. Personally, I wouldn't SOA stock 30/20 axles. Narrow or wide track. But everything has it's pro's and con's. And price tag.

One of the reasons the ride quality is what it is, other than the straight axle leaf spring suspension, is the short wheelbase on a CJ5 . Lot's of 'bucking'. Lengthen the WB, and the ride improves.

The narrow track, if running OEM size tires, and stock suspension, will still cause center of gravity problems in 'panic' or 'emergency' maneuver situations. If you're comfortable with the handling quirks, and you are not 'stuffing the tires' on a regular basis, then you can easily run 35" tires on a CJ5 with a 4" SUA + 1" Body Lift + aftermarket shackles. However, lots of wheel spin (Mud/Snow/Ice), large tires, and subsequent 'shock' when the tire gets instant traction, will cause problems with the light duty Dana 30 . Consider a truss for the AMC20 . Also, your turning radius will suffer, as the larger the tire, the more it will contact the front springs or sway bar (see above pic for that too).

Also consider that larger tires will put additional work onto the stock braking system.


Everything has it's downside when modifying a CJ. Sometimes, it's just more cost effective to go out and purchase a nice used Rubicon.....

Edit: I realize you are asking about bigger axles, so honestly, had I to do it over again, I would have went with a custom 44/60 set up from Dynatrac or another builder. Instead I put way too much $$$$ into the 30/20.

 

[SD78CJ5]

I think there were a couple of "add a leaf" lift kits installed.

I plan on going disc all the way around, and may convert to power brakes. First I've gotta figure out what it is I gotta do with this suspension as it's the biggest pain right now, and being that the axles are pretty tired and I don't want to put money into them anymore it just made sense to me to go full width for stability and to fill in my 6" flares a bit more.

There aren't any holes or anything for a plow I think it was just the PO's cheap way of getting 33's on it (which rubbed during a small flex test).

 

[HackFabrication]

At one time or another mine had a snowplow, or was dealer 'prepped' for one. Basically they had a frame brace that was welded to the outside of the frame. The plow attached through existing holes other than a couple that were drilled further back down the frame.

This is my 76 CJ5 with the 2.5" BDS lift, poly body bushings (stock height), and 3/4" ConFer shackles (3/8" lilft):



Other than the roll cage, windshield, and the passenger seat it's pretty much at 'normal weight'. No problems with the 32x11.50-15 TSL/SX tires fitting, other than turning stops needed to be adjusted. I believe I can get a set of 33's under it (and possibly 35's) for strictly street use. But even with the small lift, the center of gravity has changed somewhat. Additional tire diameter is going to amplify that condition.

Like I replied, from a pure dollar for dollar and strength for strengh comparison, I should have went with the custom 44/60 axles. Maybe not full width for a CJ5 , but at least wide track.

I've seen a few beastly CJ5 's. 42's-44's, SOA or custom 4-links, Dana 60's, big blocks. I doubt if many of them are used daily on the street.

 

[SD78CJ5]

I've made up my mind for now to go with the rock equipment granite kit from ok4wd. Rock Equipment Granite Kit | OK4WD

I'm going with the ARB Suspension (OME) springs which give me around 2-1/2" lift. I also plan on flipping my tie rods to get that clearance I want. From the pictures I've seen it looks like the springs aren't gonna be too bad being under the axle.

This will allow me to get a set of dana 60s and build them up, as well as give me time to plan out my coilover suspension.

Thanks for the input guys! I'll be sure to start my own build thread once I get rolling on this.