99skyline99

I recently just bought a new 2015 JK sahara auto. My ultimate goal is a run 37s and keep it a semi daily driver. (Probably 4 times a week) Now I have an insane amount of questions so i can build it to suit me right the first time. I was going to upgrade to the D44 up front but I'd really like some input on which one i should go with, the spicer, the prorock or which one is best? Should i truss the front and rear to keep the axles from bending or would they be fine? I wheel maybe once or twice a month and nothing too crazy. I live in Colorado so N/A engines here suffer on power so would 4.88s be good enough or would you recommend 5.13s? Would i need chromaly shafts and upgraded drive shafts or would the stock ones be fine? I'm also planning on getting E lockers, or would ARB be a better choice? Any other input on anything that i would need to upgrade axle/ drivetrain wise would be a HUGE help. Thanks everyone and happy jeeping!

bl17z90

Awesome man! Welcome to the Jeep world



Based on all of the research that I have done Dynatrac is the way to go. I havn't actually gotten a chance to really run my new Prorock 44 yet but I'm sure it will serve me well for many many years. There is no reason to do any strengthening to the Prorock but the rear can have a truss added but I have never actually spoken to someone who has broken one. I'm sure it has been done though.



I'm actually not 100% sure that would be an issue or not when comparing the 2 gear sets. But either way I would always recommend 5.13's even with the 3.6. It will help your crawl more than the 4.88's and the RPM isn't much higher at all.



When you buy a new axle you should also pick up a set of axle shafts for that particular axle. The Prorock 44 for example requires custom length shafts when running the non Rubicon gear setup. You can get them from Northridge4x4 or Dynatrac directly. A few different companies make them. As far as shafts for the rear, you will need to get new shafts when you get the locker for the rear so that the splines match up. An ARB locker for example, requires 30 spline shafts and the stock JK has (27 I think??).



I would always recommend ARB. They just have a great track record when it comes to use in the JK.



You will want to update your front drive shaft sooner than later. If you plan on doing all of this work rather soon I would do the front drive shaft at the same time as the axle swap. That way you can have the axle built with the same yoke as the drive shaft you intend to use.

99skyline99

Awesome man i appreciate all the help. Now, any links you want to send my way with all the cheapest prices on everything? Lol. Looking forward to upgrading from my TJ

nthinuf

If you decide to replace, what is your budget?
If you decide to build, are you doing any of the work yourself?

There have been several very long 'build vs buy' and 'which aftermarket axle is best' and 'skip the aftermarket 44 and go straight to a 60' threads in just the last few weeks, so if you don't get enough feedback, or if it just takes a quick detour into total unhelpfulness (which is very likely), do a little searching and read through them.

The D44 eaton e-lockers have very good reviews, and should be on par with arb. The eatons have had better feedback lately just due to the simpler electric activation, nothing to do with arb quality, they are still top notch.

Leave the shafts alone until there is a reason to upgrade. Chomo's should come in whatever front axle you choose. Driveshafts will depend on lift height, and axle choice if you end up with something bigger than a replacement d44.

Gearing is another area where you will get a lot of conflicting information. Start by opening the FAQ's stuck right to the top of this modified area and finding the rpm charts. Don't look at the colors so much as note the rpm ranges, might be useful when reading the recommendations you get. And remember to use actual measured tire size, not mfg height spec. And also note that people make suggestion because of what they have, where they live, the type of driving they do, the specific year/model/engine/transmission they have - and none of it may actually apply to you. So just a heads-up to read into the replies...

99skyline99

Yeah I've been reading up on the 60s and I've seen a deal for 12k fully built front and rear 60s with arbs. But honestly i was hoping to have the axles built and locked for around $7k. I know the 44 front is about $2k and then for an eaton is about $1k an axle. I am honestly too busy and kinda too scared to do any of the welding and cutting to install the front so I'll have a shop do it. Whats usually the price for an install like that?

nthinuf

A fully loaded PR44 is right around 5k. Then slap the brakes/hubs from your 30 on the ends and bolt it right up. Northridge4x4 has an axle builder on their website where you can choose some options and get pricing updates, worth a look. Teraflex, G2, Currie also have d44's to consider. And there are a few others like the j8 to look at, and even crate rubi44's.

For 60's/14b's, check out Fusion4x4. Haven't seen any posts recently, but they build from existing axles to save a good chunk of change.

And depending on your actual use/needs, remember that you can just run the stock axles until there is a reason to upgrade.

jedg

Howdy, if you haven't already, I recommend you read DirtMan's post - https://www.jk-forum.com/forums/modi...-lifts-288269/

larry0071

I built my JK for 37" tires after exhaustive reading across multiple forums. I have one thing I will tell you... In Ouray/Telluride/Silverton and at 13,000 feet.... I thought the engine was failing. I was in low range, 1st gear, holding it on the rug and it would manage around 7-10 MPH tops on the steep climbs. But then I'd get back down off the mountains and it ran just fine and normal. So as you see from my build, 4.88 gears are great everywhere but at the highest peaks. Now don't get me wrong, I made it... it could always keep climbing.... but there are times where your giving it all it has and there just is no more. But it keeps climbing. Slowly.

This year was 14,000 miles since the build, around 1,800 miles were off road. I have not touched since the re-tighten party on a mountain top in Colorado where I discovered that half of the fasteners had worked loose when we heard a thump in the steering. We screamed everything tight and never had to touch it again.

Longlegs

I wheeled Ouray with my 15 rubicon w 4.88 and 35's and thought it was spot on for gearing. But I have a 4/1 transfer case. The gearing on the road was right where it should be, even though the rpms seemed high. I got 16mpg on the trip (Front hubs unlocked on highway). For 37's I'd seriously look at 5.13's. regarding front axles, everybody talks about strength of housing for aftermarket axles, but all the 44's use the same crappy unit bearings. It's something to keep in mind when running big tires.

larry0071

I thought about that unit bearing and ball joint thing. Both are not typically instantaneous catastrophic failure items, they are wear items that you notice failure over time and can respond to them as soon as reasonably possible.

Or like me, I store my JK in the winter and when it comes out in the spring for the 2017 updates, it will get unit bearings on the PR44U as part of the new season refresh/update since I am running 3" backspace with a large tire.

The Synergy balls should easily last 25K miles with regular greasing, so I'll swap them for 2018 (10K-12K miles a year). I look at the shafts, gears, housings as show stoppers. The things that have you 10 miles into the woods/mountains and break, forcing you to be stopped and done, screwed in a bad way. I really feel that my next set of balls will be the Rare Parts, that leaves only one simple minor weakness, the unit bearings that are held on by 3 bolts and can be changed very quickly and easily.