Zebvance Posted September 25, 2012 Share Posted September 25, 2012 My brother Has a 2007 jk unlimited and he just bought a dana 44 axle housing from a Rubicon to replace his dana 30. My question is are the upper and lower control arm mounts and what not in the same place and will it bolt up? also is it worth the swap? Is it a up grade from my dana 30? what the spline count on mine vs his? Also if I don't want it he asked me what He could sell it for? any ideas? Link to comment Share on other sites More sharing options...
Zebvance Posted September 25, 2012 Author Share Posted September 25, 2012 oh yea forgot to mention, the PO that did the 4x4 swap on my MJ, and pulled the axles from a xj, not sure which year though. However I do have the numbers from the front axle tag if that helps..... Link to comment Share on other sites More sharing options...
skidoo_j Posted September 25, 2012 Share Posted September 25, 2012 I would say it's not worth it. The one you have should be high pinion. IIRC the one out of a jk is low pinion. You can use randy's ring and pinion's website to compare the spline but the high pinion revers cut is stronger and provides better angles then the lower. the main thing you'd gain pending what year the current axle came from is if you had the axle disconnect. Link to comment Share on other sites More sharing options...
Zebvance Posted September 25, 2012 Author Share Posted September 25, 2012 I would say it's not worth it. The one you have should be high pinion. IIRC the one out of a jk is low pinion. You can use randy's ring and pinion's website to compare the spline but the high pinion revers cut is stronger and provides better angles then the lower. the main thing you'd gain pending what year the current axle came from is if you had the axle disconnect. how do I check that? Link to comment Share on other sites More sharing options...
xjrev10 Posted September 25, 2012 Share Posted September 25, 2012 how do I check that? First of all it's not a bolt in affair. JK axles are wider then XJ/TJ/ZJ axles. High or low pinion. The pinion comes out of the axle centersection ABOVE the axle tubes on a HP, and below on a LP. I know for a fact every TJ got a LP30. I honestly haven't been around enough JK stuff to Know if all got a LP30, but I would guess they did! Link to comment Share on other sites More sharing options...
mvusse Posted September 25, 2012 Share Posted September 25, 2012 On top of that the JK unit bearings use a different wheel bolt pattern. Link to comment Share on other sites More sharing options...
Eagle Posted September 25, 2012 Share Posted September 25, 2012 The TJ front axles are bolt-ins, but they are low pinion. Aren't the JK axles 4" wider? Link to comment Share on other sites More sharing options...
Bounty Hunter Posted September 25, 2012 Share Posted September 25, 2012 4" or 5" wider, not to mention prone to balljoint failure and the inner-C's easily bending. I wouldn't do it, not worth the hassle. Link to comment Share on other sites More sharing options...
Zebvance Posted October 1, 2012 Author Share Posted October 1, 2012 ok thanks guys! Link to comment Share on other sites More sharing options...
Globex Posted October 3, 2012 Share Posted October 3, 2012 We have a set (D30/D44) in our shop mj going together right now. The d30 in JK's is HP. The brackets I got were from Dynatrac. The upper control arm mounts are in the right spot and the lowers are close if you wanted to use them again. They do put the lower control arms a little off but it could work. We just cut them off and welded new ones on that were thicker anyway. I also sleeve and gusseted the axle to add a little strength to them. Going to run some synergy ball joints to. The brakes are larger then MJ stuff and you end up with crossover steering. The drag link is a stock JK setup cut down about 3 inches or so. Used a trac bar from a old TJ build we had around. Both yokes were changed to 1310 yokes. The rear we ended up just going spring over with a jk44. The axles are around 5" wider overall but if you use stock rims they don't actually stick out that bad. It was a pretty simple swap overall if you are ok welding. Link to comment Share on other sites More sharing options...
Eagle Posted October 4, 2012 Share Posted October 4, 2012 The axles are around 5" wider overall but if you use stock rims they don't actually stick out that bad. It was a pretty simple swap overall if you are ok welding. Did you install the reinforcing sleeves in the front axle to prevent the Cs from bending the tubes ( which is generally what happens with the JK front axles)? The reinforcements are smaller tubes that are a slip fit or light press fit inside the stock tubes, and are then welded in place to beef everything up. Don't even consider using a JK axle for off-road if you're not planning to do this modification. Link to comment Share on other sites More sharing options...
Garvin Posted October 4, 2012 Share Posted October 4, 2012 I really don't see the advantage of a JK axle. With the same amount of work, you can fit 3/4 and 1 ton axles in there without any of the bending issues. Link to comment Share on other sites More sharing options...
Globex Posted December 3, 2012 Share Posted December 3, 2012 I did sleeve and gusset the front. We do this a few times a week on jk's at the Shop. I used rse sleeves and evo gussets. We get a few spare axles from jk's doing dynatrac axles. So they didn't really cost anything. The only real expense I had was ruff stuff for the rear and got dynatrac to send me the brackets for the front and the sleeves and gussets we had around. Link to comment Share on other sites More sharing options...
xjrev10 Posted December 3, 2012 Share Posted December 3, 2012 I really don't see the advantage of a JK axle. With the same amount of work, you can fit 3/4 and 1 ton axles in there without any of the bending issues. Bending issues..... Yer talking about a vehicle bending a axle that weights almost 2 times as much as a average MJ.... I don't think there would be any problem using JK axles in a MJ if they can be had for a reasonable price. But most of that stuff might as well be coated in gold. Specifically the Rubi D44s. Link to comment Share on other sites More sharing options...
Eagle Posted December 3, 2012 Share Posted December 3, 2012 Bending issues..... Yer talking about a vehicle bending a axle that weights almost 2 times as much as a average MJ.... I don't think there would be any problem using JK axles in a MJ if they can be had for a reasonable price. But most of that stuff might as well be coated in gold. Specifically the Rubi D44s. Are you saying a new Wrangler weighs twice as much as an MJ? If so, you need to check your specs again. You're wrong. The problem is that the JK "Dana 44" is the same hybrid, pseudo Dana 44 that was used in the TJ Rubicons, with the same thin axle tubes and small outers -- except that they made it wider, which means there's a longer lever arm working the axle tubes against the diff housing. It's okay for street use on factory-size tires, but bigger tires and the stress of off-roading is too much for it. The tubes bend. That's been well documented, and written up in many of the off-road magazines. You may not choose to accept it, but it HAS been well-documented. The fix is as described above -- install sleeves inside the axles to effectively increase the wall thickness of the tubes, and gusset the outer ends where the Cs are mounted to the tubes. Link to comment Share on other sites More sharing options...
xjrev10 Posted December 4, 2012 Share Posted December 4, 2012 Are you saying a new Wrangler weighs twice as much as an MJ? If so, you need to check your specs again. You're wrong. The problem is that the JK "Dana 44" is the same hybrid, pseudo Dana 44 that was used in the TJ Rubicons, with the same thin axle tubes and small outers -- except that they made it wider, which means there's a longer lever arm working the axle tubes against the diff housing. It's okay for street use on factory-size tires, but bigger tires and the stress of off-roading is too much for it. The tubes bend. That's been well documented, and written up in many of the off-road magazines. You may not choose to accept it, but it HAS been well-documented. The fix is as described above -- install sleeves inside the axles to effectively increase the wall thickness of the tubes, and gusset the outer ends where the Cs are mounted to the tubes. A built 4 door JK is 7500-8000 pounds. OP has said nothing about his MJ being modified. My 88 LWB weighs about 4100 full of fuel with me in it. I'm looking at running JK44s in my trail rig project, so yes I have done my research. Modified axles IN heavy boat anchor JKs the bending is a problem and rightly so. Now I'm not saying you are or are not going to bend a axle from a JK in a MJ just you would be hard pressed to bend one in a stock MJ which presumably is what the OP has.... Link to comment Share on other sites More sharing options...
mvusse Posted December 4, 2012 Share Posted December 4, 2012 My MJ weighs in around 5,000 pounds. Adding up the modifications I come up 800 pounds short of that. That is probably the amount of mud inside the frame. I am in the process of installing new axles that combined weigh about 1000 pounds more than the ones under there now. My new front axle alone weighs in at about 700 pounds, the current D30 I can pick up by hand and walk off with. So over 5000 pounds when I'm done with the current mods, not counting the suspected 800 pounds of mud. I have yet see a JK (even a friend's Hemi on 40s, or another friend's 4 door with Dynatrac Axles and 42s) come in at twice that, or over 10K pounds. I'm hard pressed to believe a built 7K or 8K pounds JK would still be on a stock unmodified D30 or D44 front axle. I'm with Eagle on this one. Link to comment Share on other sites More sharing options...
jpnjim Posted December 4, 2012 Share Posted December 4, 2012 Adding another perspective, the pics I've seen of failed JK axle tubes, they didn't bend like you'd expect most tubing to, they broke, like something cast. More like fractured metal, than a split, or tear. I don't think the tubes are cast, but I don't think they are like normal traditional tubes either. Either way, the inserts seem be a pretty good solution. Link to comment Share on other sites More sharing options...
Garvin Posted December 4, 2012 Share Posted December 4, 2012 A built 4 door JK is 7500-8000 pounds. OP has said nothing about his MJ being modified. My 88 LWB weighs about 4100 full of fuel with me in it. I'm looking at running JK44s in my trail rig project, so yes I have done my research. Modified axles IN heavy boat anchor JKs the bending is a problem and rightly so. Now I'm not saying you are or are not going to bend a axle from a JK in a MJ just you would be hard pressed to bend one in a stock MJ which presumably is what the OP has.... I'm having a hard time seeing a built 4 door JK weighing that much on stock axles. 4dr JK's weigh in at 4550 and Comanches weigh in around 3090 so say a 1500 lb difference. My Comanche on one tons, 38.5x15 tires, and a cast iron V8 weighs in a little under 5000, that's with a spare, full tank of gas, and tool box filled to the brim (atleast a few hundred pounds there). Link to comment Share on other sites More sharing options...
Zebvance Posted December 4, 2012 Author Share Posted December 4, 2012 Wow this thread is still going? I just picked up a 8.8 and I think the main reason I'm going to pass on the free 30 from my brother is that its going to take just as much work to make it work than just putting a waggy 44 under it. Link to comment Share on other sites More sharing options...
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