Looks awesome!!!

Some questions/clarifications:
What gearing are you on?
Did you stay with the Ford 44 front and 9 inch rear, or do a 609 build?
If you dont mind, about how much do you think you have in the axles?
Would you buy built axles or do the build again?

 

These are JK Dana 44's. The front is out of a Rubicon, the rear is a non-Rubicon. They have 5.13 gears. I will do a full tech post detailing everything I used soon. Ballpark cost of what I have into it: way, way too much. Truthfully, $6,500? Wow, that number sucks after adding it up, but it was spread out over years, so didn't feel so bad. That's not including wheels and tires.

Buying built axles is definitely way cheaper, but the front end I bought I'm fairly skeptical of the gear setup and the locker. Good chance I end up needing to rebuild that. I feel like I've gotten burned on a lot of the things I've been buying on marketplace. There's a reason everything is half price.

Honestly, if anybody was looking to follow my path, I would say sticking with OEM axles is the way to have the most amount of fun for the least amount of money. For somebody committed to a swap, the JK stuff is an excellent choice. I still sometimes wish I went 9 inch rear, but the 44 rear is pretty great. We'll see how these hold up in the long term. I do wish I had a ProRock or J8 housing up front as the factory JK stuff is still just 2.5" diameter 0.250" wall tube, but with the truss and gussets I'm confident in it.

 

Thanks for the info!

I've been debating about going up in size for a very long time. Seems that now, after speaking with many others, that buying a front axle is better/cheaper-ish than building. The rear is kind of a toss up.

I like the idea of half-ton axles and not going with 1 tons due to the weight. Seems you can build the axles you mentioned fairly well to be strong. However, if you start going up in tire size, then you may want to go to tons. But if you stick with 37s you should be golden.

 

I think the "factory" wheels look rad! Gives it a bit of an off-road sleeper vibe.

 

Thank you for saying that! That is kinda the vibe I'm going for. I'd like to have the "least offensive" XJ possible while also having it be extremely capable offroad. Now, I recognize I am saying that with a window full of stickers and garden edging screwed into my front fenders, but that's the intention.

The wheels have been growing on me. I don't hate them as much as I did at first. I do like the "factory" look. I played around with photoshop a bit and I think painting them just a hair darker would be nice, but I'm not gonna jump right into that because I don't want to ruin the nice finish on them.

 

Update after driving it for a week putting about 300 miles on it:

It’s really good and I’m very happy with it, but maybe not quite the euphoria I had last week.

Low gears don't behave exactly how I thought they would. I still find myself needing to shift from D to 3 to make hills frequently. I’m wondering if I need to do an ECU reset or adjust my kickdown cable or something to get the trans to shift when I expect it to.

The brakes are really good, but maybe not “OMG put you through the windshield” good. Pedal is a hair soft, but I’ve also been used to a very firm pedal from an oversized master cylinder for a long time.

The handling is a big improvement, but it still drives like a lifted Jeep. Some corners are still a two-handed operation at the speed limit, and there are still times it takes full attention to drive. It’s certainly not my F-150. I do wish I had a sway bar and a steering stabilizer. Also haven’t gotten it in for an alignment, so I’m curious what specs I’m actually running at.

The tires are pretty rough. 2 of them are excellent, but the 2 I put on the front are cupped pretty bad and I think are causing a lot of my noise/vibration. I pulled my front driveshaft as a first diagnostic step, but that didn’t change anything.

I took it for its first highway run yesterday. I literally said “wow!” out loud after I accelerated up to 70 because of how easy it was and how much everything smoothed out. Does better at 70 than 55 lol.

One good thing is the steering and suspension are tight right now. No noises at all from anything, which is pretty crazy.

Except…

Remember that photo of my front diff full of metal shavings? Well another bit of evidence that something is going on in the front was that after I installed my axle shafts, I noticed there was a tight spot when rotating the carrier through the spider gears. Everything felt fine when turning the pinion, but turning the shafts against each other had something up with it.

Now that it’s on the road, I have a pretty overbearing oscillating drone that I think is coming from the front. It’s more pronounced at certain speeds than others, and the timing changes as I go around long sweeping corners.

Yesterday I bought some stock JK takeoffs to help diagnose some noises and vibrations. These JK Moab wheels are actually what I had originally wanted to run before finding the Mopar Performance wheels. Good thing I didn’t, because they didn’t clear the brakes in the front.





I found 4 washers stacked behind the wheel was the sweet spot to get them to fit lol. These would work with 1 inch wheel spacers.

So that was unfortunate, but I rotated my 2 good 37’s from the rear to the front and kept the Moab’s out back for now.

While doing this I got some photos of my 37’s at full cut and realized I’m not actually hitting the steering stops. I don’t actually know what’s stopping it from turning farther. Doesn’t appear like anything is hitting.





This steering angle is going to cause me problems anyway because the tire ends up under the frame rail at full cut. It’s fine on the road but I won’t be able to flex and turn sharp at the same time. I had hoped the extra width from the axles would help but with the narrow backspaced wheels it pretty much evens out.

I ran the rig up the road with big tires up front and little tires in the back hoping to get some clues about what to do next. I immediately noticed it had much less tire noise and vibration. Those cupped tires are causing problems. It was also funny to get the rig up to 65 mph and see 90 on the speedo lol.

Drone noise is very much still there unfortunately. Next step for me is to pull the front axle shafts and drive it like that for a bit. One great thing about the JK axle is the unit bearings are self retaining and do not need a stub shaft in them to keep them together. I should be able to drain the fluid, pull the shafts, and run 2wd mode.

 

I pulled the shafts today. Didn’t like what I found.

This fluid has about 300 miles on it and it wasn’t a fresh rebuild. I bought this axle built on Facebook Marketplace. Awfully shiny. It’s producing a lot of metal from somewhere.




So that’s very unfortunate. I left the carrier in there for now. I’ll get back to it after the wedding. I’m not really sure what is causing this to happen. Going to need some noggin’ pokin’.

After getting it back together without front shafts I took it for a drive and found the noise I’m concerned about is still there (maybe?), and to me sounded like it was still coming from the front, but it’s hard to tell. I noted it resonated strongly at 40 mph with little tires in the back.

Went back home, put the 37s on the rear, and went back out. Same thing, loud resonating drone at 40.

It has to just be tire noise. Nothing spinning in the front and resonating at the same ground speed with different sized rear tires leaves nothing but tires to be the problem. It just sounds and feels like a more serious noise.

I’d like to get some wheel spacers to run the Moabs all around and eliminate the 37s from the equation. It’s been 10 years since I’ve had smooth quiet tires on this vehicle. I think it would be a good diagnostic tool.

 

First time I've seen 37's on an XJ. Great build.

 

Thank you! Stay away from Pirate4x4 and Irate4x4 lol. Those guys will stick bad ideas in your head,

I'm going back and forth over whether 37's are for me. They might not be a permanent thing. We'll see.

Just did the 500 mile fluid change on the rear end yesterday. All looked as expected. Will be driving the rig 3 hours at the end of this week. Hopefully all goes well. I am concerned about my muffler being too close to the floor and absolutely baking the floorboards. Its hot enough to char anything on the floor right there. Definitely need to lower the exhaust a hair, but I do not have time for that at the moment.

 

Wedding has come and gone, and my was it quite the time! Everything was perfect. Weather, people. vibes. There's nothing I could've changed to make it better.

Jeep did good! No drama, save one pretty major incident...






Blew a tire out at 70 mph on the way there! Go figure lol. What a story. No worries, was able to get it changed and we were on our way.

It doesn't look like I hit anything. There is about a 2 inch split on the inner sidewall. Looks like it actually just blew out. This is likely what I get for buying 10 year old tires on marketplace. Had the thing on the highway for all of 10 minutes. I suppose that answers my question about whether or not I want to keep these tires.

Other than that, I will say the thing was struggling on the highway. It still could barely maintain 70 mph and was needing to hold 3500 rpm to pull hills. Every time I go up a long hill I get a burning plastic/rubber smell which I think is from the exhaust baking the sounded deadening over the muffler. I'm hoping its just because the muffler is too close to the floor, but part of me is concerned there's something not running right and the cat is blow torching the muffler whenever I'm under load. I'm not entirely sure how things should be operating. Makes me wish I could drive a bone stock XJ in good condition for comparison. I keep meaning to grab some temperature measurements but I've forgotten a few times now.

Steering/handling is meh. Audrey commented on how it is twitchy (from the passenger seat). It still can dart off to a side during braking, and generally still drives like a clapped out XJ. On the way home we drove a backroad the whole way instead of the highway, and the twisty/turny/hilly/bumpy route had me wanting more as far as drivability, and the exhaustion of wedding/lack of sleep/hangover had me wanting a quiet rig that I don't have to yell at my passenger for them to hear me. It was a long ride home.

So, next things I want to do are get this in for an alignment, and to space the exhaust down a couple inches. I also ordered some spacers to use the Moab wheels on the front end for a little while to rule out mud tire characteristics from the diagnosis of everything else.

Still pretty thrilled that I got to take the rig to the wedding. It wouldn't have felt right if we didn't.

 

awesome update! Congrats on getting married.

Yeah I wouldn't buy 10 yr old tires. Unless you keep it more of a trail rig. May save them for just trailering to the trails and such. New tires will also ride much better as well.

 

No need to pay for an alignment: https://gojeep.willyshotrod.com/HowtoAlignment.htm

It's wicked simple to align these things in the driveway. Toe and caster are the only two things to set. I bought to make setting toe easier. Caster is a little more entertaining, but still simple to set. Caster is a balance between drivability and front driveline angle. Sounds like you need some more caster.

 

I agree that its simple to do a rough alignment at home, but I want the printout.

Toe is easy enough to get close. OEM spec is between 0 and -0.45° with a nominal of 0.25°. Measuring with a 24" bar, that's a difference of .105" nominal and .188" max. Measurable? Absolutely. Easy to be precise? Eh, not so much. How straight are those bars? Are they clamped well? Are the wheels straight? Etc. Plus, having large tires adds in some questions. Do we want to stick with the same angle as OEM, or the same amount of scrub? I would think angle as the contact patch on the ground is not effected nearly as much as the significantly larger diameter tire, but one could debate either way.

Caster is easy to do by feel, but I would love to have actual numbers. I also am very interested in knowing how each side compares to the other. I can't take any measurements from my pinion or diff cover because I rotated the C's, so any factory established relationships are gone.

The real question I would love to put numbers to is my thrust angle / setback angle. My wheelbase and centering of my front axle are all tape measure set to brackets that I have welded on. Its all probably good enough, but I want to put numbers to it and try to get it as good as I can. These values are hard to do precisely in the driveway when there are so many variables which have changed.

 

I hear you, but I don't see the value in it. Knowing the numbers does little to improve the handling of the jeep. I aligned mine almost 10 years ago when I built it, and it ran down the road nice for all of that time (it was on CADs, with 6" of lift and 33s). I am in process of finishing up a long arm install and plan to do the same 'driveway alignment'. If I can't get it running down the road good again, then I will eat my words then and pay 'the man' for an alignment. If that day comes I'll be sure to tell you, 'you were right'.

 

Bought some wheel spacers to get the stocks mounted up on the front. Been driving around like this for a week or so. Sure looks goofy lol.






Good news from this: my droning noise is gone with this setup. Thinking the cupped 37's are causing me headaches. Next step is to put the front axle shafts back in to get the front end spinning again with these tires and see what that gets me.


Still haven't done anything for alignment. I contacted a couple people who I thought would be able to do it. Didn't have too much success. Not the biggest priority.


I've been amazed at how fatiguing the Jeep has been to drive. Idk, maybe I'm getting old, but the NVH on this thing sucks. I used a sound meter app on my phone to record some data. I found over a test run an average of 76.5 dB(A) with a max of 93.9. In comparison, my F150 was 62.3 dB(A) average and 71.9 max.

The peak loudness was mostly engine noise from going up hills. I feel like something has changed on my setup because now my cowl intake seems very loud and my exhaust is not nearly as quiet as I would expect. Its a brand new Walker Quiet Flow, and it barks.






I also have been fighting exhaust heat on the floor over the muffler. I measured 225°F on the interior of my floor after climbing the long hill up to my house. I made this other thread about my hot floors issue for more details there. Unsure if I just need better heat shields, or if there is something else going on.

I feel like the rig isn't running the heathiest. When we were on the highway headed to the wedding, I could barely hold 70 mph. Recently driving around with 5.13 gears and stock sized tires, it doesn't have the snappiness I would expect. It starts right up and runs fine when cruising around, but getting on the gas hard isn't impressive. Seems like its struggling.

The hot exhaust got me curious about data. I bought a bluetooth scanner and have been monitoring some signals while driving. I've never looked at this data before and have really no knowledge about any of it, but I figure its good to learn and a good time to get into it.