Rear Axle

spnkzyj

Member 2024
VA4WDA
Planning for late 2022/early 2023 (or if it breaks before then), looking at Rear Axles for the YJ. I know there are lots of options, however, I do know I'm going to keep it simple and order a complete ECGS rear. I've heard nothing but positive reviews of them as a company, I have dealt with them personally and thoroughly enjoyed, enough to go back. Next, I know I want an OX locker. Lastly, you know I want to wheel the heck of the rig, currently running 35s, have no plans for 37s, but we all know how that works, looking to stay 4.5x5 lug pattern, with option of 5x5 maybe one day.

Now that those parameters are set, here is where my questions start. Original plan was Ford 8.8 with C-Clip elim, 35 spline axles, Ox Locker, disc brakes. Looks like they are pricing and phasing those out in favor of the Dana 489. I started building it and it's cheaper than the 8.8, which I get if they are trying to phase out the 8.8. However, what about their stock width Dana 60 with the 4.5x5/5x5 option? I feel like the Dana 60 is heavier and losing ground clearance. However, I can't think of anything I can't do if I go Dana 60, but not sure I'll ever need more than the 489. About $650 diff.

Yes, I know, I will talk this out with ECGS, but want to get my head straight before I do. Just looking for opinions. However, after last nights HOA meeting I'm beginning to think I don't want or like people's opinions much. :ROFLMAO:
 
Start with Power and torque and wheeling style.

Still planning on running the 4.0L? a D44 will hold up well
4 speed T case in the future? if not again the D44 will hold up well.
Wheeling style, this is where the rubber meets the road. If you drive with a lot of right foot then build the axles bigger and stronger. If slow and technical is you style then a D44 is plenty good for the Job.

Parts availability and aftermarket parts favor the D44/60. Just too damn many out there not to support.

Stuffing the D44, Slectable locker, 4140 or 4340 axles I would go 4140 as they still allow for some twist and will spring back and are a bunch stronger than the stock 1500 heat treat series. Up front consider RCVs. I have run mine for 105,000 miles without issue or complaint.
Bolt pattern, investigate 5x5.5. Why? this allow you to run locking hubs so if you are running it down the street less wear and tear on the front end components and slightly better fuel mileage.

Somethigni of note, Rattletrap55 runs a CJ7 on the stock rear. He is runnign 35s this year, the past was a 33. wheeled hard trails with no issues at all with the stock axles. His biggest problem was a locker in the front and a LS in the rear. This led to blowing up locking hubs each trip. since going to selectabel lockers the hubs have survived many trips. And then there are always those guys upgrading the D44 to D60s...I know of a few package deals on D44s some include wheels

Rob

Just information not an opinion.
 
Master "dreams"

Atlas 4 speed box
4 link
~300-350 hp something
35's make sense, whcih I have now, but 37's could be something if I get really stupid

Now, if this all happens in the YJ, or I go find a TJ/LJ as a starting point, that remains to be seen. Who knows, maybe I'll get really dumb and get me a 70s Jimmy or Scout.

Correction: both 489 and 60 come drilled 4.5 x 5 and 5 x 5.5 not 5 x 5.
 
Based on your stated needs, I'd stick with a Dana 44. The 30 splines are more than enough for 35" tires, even in hard wheeling. The 489 might be a choice, if you ever thought 37" tires were in the mix. However, at that point you might as well make the swap to a 60. Other benefits of the 44 are standard parts, lighter, and better clearance. Plus, I believe it will be cheaper. FWIW, the standard lug patterns are 5x4.5 and 5x5.5.
 
Master "dreams"

Atlas 4 speed box
4 link
~300-350 hp something
35's make sense, whcih I have now, but 37's could be something if I get really stupid

Now, if this all happens in the YJ, or I go find a TJ/LJ as a starting point, that remains to be seen. Who knows, maybe I'll get really dumb and get me a 70s Jimmy or Scout.

Correction: both 489 and 60 come drilled 4.5 x 5 and 5 x 5.5 not 5 x 5.
If you have desire of a 4 speed atlas..... ditch the idea of 300+ hp. The reduction gear ( planitary is not designed for big HP numbers) will not hold up. I would think toward a 4:1 or 5:1 two speed box with a bigger power plant in you master dream.

I have watch over the years how easily The CJ follows the Red Jeep in some of the toughest trails on 33s.... tummy tuck in place and 35 inch rolling stock, that thing will be unstoppable. Don't get caught up in the bigger is better I have seen plenty of big tired rigs stuck on challenges that the CJ cruised thru. Your advantage in the YJ is a short WB this is also a disavantage in going big. good lines and carefull spotting you YJ will be a beast. gearing and traction are your fiend. I have watched Rattle trap 55 do the lower part of rock creek as well as death trap on 33s.... it is all about the line. But if you are going rock hopping with a fire breathing LS..... bring buckets of money or raid the Junk yard for a F350.... and invest in a good 4 point harness. LOL.
 
As usual, appreciate the input.

I wasn't looking at the 11.7:1 or 10.34:1 4 speed boxes. Was eyeing the 8.16:1 box. However, as I've realized, the build has been around necessity, and I haven't gotten there yet. I just liked the idea of not having to go 4.88 or 5.13 on the highway, but getting those kinds of gains, or better, on the trail. slowest with current setup would be a crawl of about 1.46mph, compared to the 8.16:1 box of 0.55mph. 1mph gain, or better yet, option, makes sense of a technical/on paper concept. Along with the torque multiplication.

I agree tucking on 35s should be plenty, but if I do go 4 link, I'm sure it'll get stretched while I'm there, which then is where I could see myself questioning 37s. Again, I have no plans on going 37s or larger, not a goal, I just like to know what box I'm building myself into.

FWIW, I reach out to ECGS and asked, "What would you consider to be the determining factor to switch from the 489 to the 60?" Already got a response and it was going larger than 37s or big hp. Followed up with is ~350hp considered "big", to which was responded to as, 350 is not a concern, a 489 will handle that just fine.
 
Just wanted to throw out the option of their competition 9" although I do not know if there is an OX locker option for that. When I bought one for our CJ there wasn't much price difference between it and the 489
 
I would say the D44 would be best given all the reasons others have said above.

I know you said 37s is way off in he distance but if you are really considering it, you may want to do a lot of research. I have read some about 37s on a TJ and everyone says it is not realistic unless you are building a true fully dedicated off road rig that will NEVER hit pavement. I would think the same would apply to YJs. I don’t think it would be impossible but it is a step that would drastically change what you could and could not do with your Jeep.

Just a thought.
 
I know you said 37s is way off in he distance but if you are really considering it, you may want to do a lot of research. I have read some about 37s on a TJ and everyone says it is not realistic unless you are building a true fully dedicated off road rig that will NEVER hit pavement. I would think the same would apply to YJs. I don’t think it would be impossible but it is a step that would drastically change what you could and could not do with your Jeep.

Just a thought.
This is very true. The short wheelbase of the YJ and TJ limits their practical use to a 35" tire. Anything bigger than that and a stretch comes into play. That means a lot of money and thought. At that point, you're doing nearly the same work for 37s that you'd have to do for 40s!
 
4
As usual, appreciate the input.

I wasn't looking at the 11.7:1 or 10.34:1 4 speed boxes. Was eyeing the 8.16:1 box. However, as I've realized, the build has been around necessity, and I haven't gotten there yet. I just liked the idea of not having to go 4.88 or 5.13 on the highway, but getting those kinds of gains, or better, on the trail. slowest with current setup would be a crawl of about 1.46mph, compared to the 8.16:1 box of 0.55mph. 1mph gain, or better yet, option, makes sense of a technical/on paper concept. Along with the torque multiplication.

I agree tucking on 35s should be plenty, but if I do go 4 link, I'm sure it'll get stretched while I'm there, which then is where I could see myself questioning 37s. Again, I have no plans on going 37s or larger, not a goal, I just like to know what box I'm building myself into.

FWIW, I reach out to ECGS and asked, "What would you consider to be the determining factor to switch from the 489 to the 60?" Already got a response and it was going larger than 37s or big hp. Followed up with is ~350hp considered "big", to which was responded to as, 350 is not a concern, a 489 will handle that just fine.
4 Link, I will agre with Runner here, if you are planning to jump from flat steel springs to coils, stretch it and look at seeing where 40 will take you. There is a company in TN, Wide open Designs that has a frame for a TJ, pretty sure the YJ is very close. The set up included a 4 link suspension with the right geometry to run big axles and big rolling stock without the big lift. At this point you might have to choose between trail rig that is streetable and daily driver that is trailable.

Deep reduction gears 4:1, 5:1 give you the torque you need and slow wheel speed off road. You might not want to run aroudn all day in Low range at 5:1 but that is why the t case is slectable. I was looking at the 4speed atlas a couple years ago and was talked out of it by Atlas due to reliability concerns with 300hp ish in the power plant. They told me yes they sell a bunch of them but it was designed for the 4 cylinder market and serious rock crawling. On paper, yes you get great gains and have some great options, now the rest of the drive line will need to live up to the increase in torque. Tally Ho's Jeep ( Bill) has a 4 speed atlas in it. he has destroyed several half shafts in the front end now and is upgrading to built(?) 44s for his 35 inch rolling stock. Same goals, as he wants a rig that can drive down the road but preform off.

John had a great point, a fabracated "9inch" housing give you great ground clearance and if done right a 10 inch ring option. Building it as a full float rear the stress and weight is carried by the axle housing itself rather than the axle. Giving you a stronger setup with dare I say less weight. Go with 40 spline shafts and there wil be no worries going to 37s or 40s or 43s

It sounds like you are heading to a trail rig that is streetable. after all you have that tow pig and sweet trailer/camper/workshop. Might need to do the monster truck thing with little rollers for the trailer and swap one outside.

Cheers
 
You are right. It will probably morph more to a trail rig that's streetable.

I do really like that Currie style high clearance 9".

The mood for today is more along the lines of the 489 rear will work great for my setup with a little room for growth. If it gets wild 4-link stuff, I'm probably going to start something new, and I'll look at different axles then. I just wanted to at least think about the box I was putting myself into and know it's limitations.

Yeah, I'm pretty sure I'm goign to have to at lease put 2 tiny wheels on to get it in the trailer now with 35s. I had about 1/2" of clearance, top down on 33s. I'm gonna try to air down to 1-2psi on the 35s and see if that will give me clearance. If not, I'll have to go that monster truck route. Been waiting 12 weeks for an axle to show up for that mobile workshop. Been rather frustrating. Need to build a bench inside and get it setup a bit better for what I'm using it for now.
 
Having run D60 in both a CJ-8 and later a YJ, I'll say its a HUGE pumpkin to deal with.
I'd build a strong D44 or 9 inch. The increased strength of the 60 is not enough to give up the clearance and weight over the 44/9".
The only reasons I didn't do that was back then there weren't the build-up parts for the 44 like high strength shafts/hubs etc.
 
I remember being in this position. Why not find a set of Waggy 44’s? Perfect for being leaf sprung and more than strong enough. I bounced mine off rev limiter and everything else on the trail and never had a single failure.
 
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