My 08 4-door has had TWO u-joint failures (in 6500 miles with about 50 of them off-road) so i'm thinking about upgrading to a Rubicon D44 up front. 4x4GroupBuy says that it will be a pretty easy swap-out but we might have to shorten the drive shaft. The wiring harness is pretty easy (12v toggle on the dash is fine). I'm wondering if anyone has put a 44 in a Sahara or X. The problem here is that I have 3.73 gearing. The idiots at Poulin Auto in NH say that there's no way it will EVER work and that I would need a total reprogram of the BCM, new drive shaft, custom gear work, etc.

So I could just keep the 30 and fix the inner axle, U-joints and yoke with some stronger after-market parts but i'd rather upgrade it to get the locker, higher spline count and be able to run 35's without worrying at all.

So the question is, has anyone done this swap and if so (or if not and you can help anyway) is there anything I need to consider or extra pieces I might have to buy? It's about $1800 bucks and if it doesn't work, i'm stuck with an unusable axle and no Jeep still so I want to be careful.

By the way, the dealership says that they wont cover this under warranty because the Jeep shows signs of off-road use! I could fight it easy but I want to upgrade it anyway.

Thanks!!!

 

I know ctimrun switched his out. no problems.

 

All you gota do is buy the new axle ($1400) and install it. the wiring kit can be had from jeep or from quadratec. your gears have to mach front to back so you will have to install new gears in the rear as well.

I would regear to 5:13 (since you have to change gears anyway), so you should change the gear in the front axle before you install it.

 

You can use the same front drive shaft as is. You will have to re-gear your rear axle to 4.10's or both to the ratio. Other than that it is a bolt on component.

 

I'm on the verge of this swap. I haven't broken my D30 yet but I'm running 35s and have been on some richter trails, smashed my stock side step, pinched my tail pipe almost shut, and other misc trail damage. I once wrote a post saying that the front locker is not nearly as important as the rear (which I have as an option on the rear) but it seems that on the most challenging trails, the places that hang me up are where one front tire is spinning wildly and another is just sitting helplessly on a rock. The one tire with traction that could pop me outa my predicament is resting easily as the other three roar and spit in place. During one particularly nasty episode is when I decided that the D44 front with the locker solves alot of problems.

I have read extensively about this swap. The front mopar D44 swaps easily into any JK. Physically it's a bolt in. I hear getting the connectors for the locker is a pain and that in your case you'll not be able to engage 4wd until you get either 4.10s in the rear or regear both. I hope I'm wrong about the connectors. Most people that have done this have wired the locker independant of the stock electronics and for good reason.

GL

 

I wouldn't go 5.13's if he's staying with 33" tires, if he's doing the 35's though then he would be good.

 

I think Piginajeep also did this swap. I intend to do it down the road as well.

 

For a sense of the tire and gear swap ratios...

Going from a 3.73 ratio to a 4.10 ratio RAISES the rpm by about 9%

Going to 35's from 33's DROPS the rpm by about 5.7%

So, if he's going from 3.73 gearing and 33's, to 4.10 gearing and 35's...he's already RAISING his rpm by about 3-4%...

IE: 4.10's and 35's is still geared lower than 3.73's and 33's.



The added expense of going lower than 4.10 (NEEDING to re-gear BOTH axles (As the Mopar Rubi axle COMES with 4.10's.....), is not really worth it if 35's are the goal.

MOST of the people who get larger tires and report giant drops in performance, etc...are still accelerating up to the speedometer speed they are used to...

...except the speedo is calibrated to the 32's or whatever the JK came with....so they are ACTUALLY ACCELERATING TO A HIGHER SPEED THAN THEY THOUGHT....and then reporting that it took so much longer to get up to that speed, etc.

They are also driving faster than they thought, and going further per mile than they thought, etc.

Remember, the JK comes with 32's and 3.21 gearing for the best mpg compromise...so whatever rpm band THAT would give at a given speed, is about what the engineers calculated/tested as most efficient.

The TOWING package, etc...option does the same thing with 3.73 gearing, gives up some mpg for some added oomph.

For rocks, etc...most of us want lower gearing than that, and we are WILLING to sacrifice some MPG to get it.

So - as far as rocks go, if you have the $, sure, go as low as you can afford to....but, remeber the hidden costs you'll pay at the pump when gas hits $4/gallon.



IE: The 4.10's are a GOOD match to the 35's.

 

I have 35"s with a 4 Inch Lift and 4.10 gears and I cant maintain 60/65
with OD on.I will be changing to 5.13 shortly.

 

Thanks for all of the great replies! It was nice to wake up today to see people responding already. Its really killing me that my 2 month old JK has been at the dealership for 2 weeks of it.

Anyway, so I think i'll try the new axle and just have the speedometer recalilbrated and maybe just put a performance chip in it anyway. While i'm in there, I might as well go to the 5.13 since there appears to be no cost difference at all.

So it looks like:
http://www.4x4groupbuy.com/store/jee...ly-p-5640.html at $1480
and two (front and back) http://www.4x4groupbuy.com/store/yuk...on-p-2827.html at $126 each plus a switch and shipping costs ($215 I think). Does that sound right?