Busted my D-30's ring gear on the JK at OFR.

For those of you who wondered how long the D-30 would last on 37’s: The answer is about 4 months, 3000 miles, and 5 wheeling trips. I busted the ring gear 2 weeks ago on OFR with the SSW. I had a mile of trail left to go and had to do it 2wd. Superior has sent new parts and it is all back together today. :sunglasses:

I’m not easy on it at all and, don’t plan on being easier on it in the future. I went to a place in Attleboro called FireBall Heat Treating. They Cryrogenically froze my gear set and bearings. It is supposed to make the gears 30-50% stronger. We will find out. :smiley:

Years ago I had a Scout II with a D30 front running 33’s and a 392 V8 (over 400 ft-lbs torque). I could basically grenade the D30 R&P at will.

Do they use a high pinion gear set on those rigs? I’m really skeptical about 30%-50% strength increase from freezing. I would need to see experimental evidence to believe it. I could believe 5%-10%.

Good luck with that.

It’s a high pinion 30. It’s not a real D-30 because it’s made by another company. It’s got a much larger Pinion in it. It shares all the parts with the D-44 on the new Rubicons. Just the Center sections are different. Even the D-44 now is different then the old ones.

As to the freezing… it’s been in all sorts of magazines. Superior Gear said that thier sponsered rock crawling rigs used to bust gear set every outing. Now they are getting an entire season out of them. Which lead me to the question of why don’t you treat them all? Apparently they’d rather gamble with the 5 year warranty.

I was talking to a guy I know that helped me build my 383 Stroker. (he builds engines for nascar teams) They are cryrogenically freezing most of the metal parts on the cars now… including all engine blocks and internal parts. He said that it makes bearing life much better.

The really funny thing is he said he can freeze a junk disposible Bik razor… it stays sharp for months. His company had started doing med/surgical knives. The knife company stopped using them. The knives were lasting too long and people began cleaning them instead of throwing them out after every surgury. Not good if your in the buisness of selling knives.

so when is the D60 going in… :confused:

are you gonna install a d60?

I will get a D-60 someday. But, for now I’m looking for a Rubicon D-44. It’s still no good for 37’s (nor the 38’s I"m going to run next) But, If I sleeve it/ truss it/ gusset it/ it may last a little better than the 30.

i wouldn’t wast my money on a 44. especially if your going bigger… and besides you’ll never get that money that you invested in the 44 anyways

If I can get a busted 44 from a JK… I can build one very cheap. I just need the center section. I’m hoping that I could purchase a center from whomever makes them now. Idealy I’ll find one in a wreck. The D-60 from Dynatrac is what I want. But, I don’t want to spend 6K on it.

X2 on not wasting your $ on a 44. You can find and build a 60 for less than 2 grand.

yup! you can probably build one for less than 2K. and that might just be a little more than what you would end up doing to the 44 but it’ll be a shyt load stronger

I’ve yet to see anyone build a d-60 to work with the abs system without buying something from Dynatrac or Currie. But, I’m looking into it. I can build a rubicon D-44 for pennies. If I could find a center case to start with. Sleeving, trussing, and gussets are just some steel.

Having built up my fair share of axles over the years (D30, D44, D60, Ford 9", and Corporate 14 bolt) I long ago concluded that if you want to do it right then its basically a wash between doing it yourself and buying ready to bolt-in unit. This statement is based on assigning reasonable value to your own time.

How many pennies do you plan on spending for the Rubicon D44 Tex? Last time I checked junkyards were getting $1,000+ for them. Here’s an itemized listing of what I have invested in the D44 I just bolted under my Jeep:

  1. Used axle: $250
  2. Detroit Locker: $450
  3. Ring & pinion: $180
  4. Master install kit: $150
  5. Cover: $80
  6. Alloy axle shafts: $350
  7. Outer bearings: $60
  8. Mounting brackets: $250
  9. Disc brake kit: $450

That’s about ~$1,800 right there and I scrapped the ABS because keeping it would have required significant custom fabrication (including precision machine work). On top of this I paid to have the R & P setup and the bearings pressed on. Those Mopar Performance JK D44’s (which I understand are actually built by Dynatrac) were selling in the $1,500 range and look attractive in comparison.

The problem I see with building a D60 for Jeeps is the width. Even with the relatively wide JK axles I think most D60’s are wider so you would need to narrow it in order to avoid unecessary attention on the road. Either that or you would need some insane backspacing on your wheels. I’m thinking that Mopar Performance also offers a D60 that bolts into the JK. I want to say the price was under $3,000. It might be worth a look.

The JK D-44 front axle with locker from mopar was 1699 they are now 3000. The rear d-44 with locker is only 1499. The axle is 5" wider than the TJ axles. A full width 60 is I believe 1" wider than my axle… which would be great. The Dynatrac pro 60’s are wider also and are 3-5K rear and 5-6K front including lockers. There is a 60 available from the mopar now for 3100. It has leaf spring mounts because it’s the part for the military version of the JK. So, still needs mods to fit the coils and control arms. No the mopar parts are not assembled by Dynatrac. And the problem with all the JK 44’s is the axle tube thickness is not very good. And the front D-44 share the same weak components as the JK 30. None of the above axles from mopar are actually Dana axles. They are made by another vendor. The pinions are larger on a JK axle. On my rear axle I’m using a Detroit carrier for a d-44 tj 3.21 down numerically. The 3.73 up one didn’t fit.

And for me… or any other JK owner… I have to fab in the wheel speed sensors if I do my own d-60. Without them my abs light will trip which will trip the entire computer system (ABS, BLD, ETC, ESC, TCS) I’d have all the lights on and not be able to inspect the rig anymore. Not to mention the truck would not drive the same and the brake system… who knows if it would work.

but you can also disable you abs bs using one of 2 methods

I want everything to work right. So, I will not dissable any of the electronic gismos. Not yet… it’s still new under warranty and making payments. When it’s a trailer queen… that will be a different story.

According to a newsfeed from FourWheeler, Mopar Performance was supposed to modify the J8 D60 rear axle so that it bolts in to the JK. Here’s the newsfeed:


Did you read the article “Far Better 44’s” in the June '09 issue of 4 Wheel & Off-Road magazine? The JK D44’s have some pretty impressive spec’s, especially the rear. Its true that the front axle tube is still 2.5" x 0.25" thick but in my view thats a good thing since this saves alot of unsprung weight. According to the article, Dana manufactures the JK D44 axles but another company manufactures the locker. Dana is one of my company’s major customers and I have a professional relationship with several engineers in the torque & traction group so I can get the inside skinny if you ever have questions on Dana axles.

According to the article: "Dynatac, in addition to supplying Mopar with some axles and being a certified Mopar dealer . . . ". It looks like the axles Dynatrac supplies to Mopar are JK D44’s that are modifed to fit TJ’s.

Personally, I don’t think you can go wrong with the JK D44’s. I was going to use them for my build except they were a tad too wide for my current wheels and I wanted lower gears than 4.10’s.

That is an old article. The D-60 from mopar needs to be converted from leafs to coils… or you need to convert the Jeep from coils to leafs. For the price of the mopar one we can buy a trail series Dynatrac with a detroit locker or ARB for a few pennies more. That unit is a bolt in + a little axle width. At the moment there are no plans to make the mopar 60 a “bolt in”. I wouldn’t be suprised to see that happen sometime in the future but, it hasn’t happened yet. I was told by a chrysler engr and the owner of Superior that the JK-D-44’s and 30’s are made by an outside vendor. Then tagged with Dana. The front axle tube is not a huge issue because we can just sleeve it. In it’s current form… they bend easily with the weight of our lifted 4 doors. The 2 Door JK’s don’t seem to be a problem. I’ve actually got the axle lean on the drivers side more than the passangers side at moment. The tubes are bending slightly.

As to the Dynatrac JK D-44’s… i’ve heard about the shorted ones for the TJ’s. But, people have been liking the wider wheel track with the JK width axles. They’ve sold lots of them. The rear JK-44 is a nice solid unit aside from the factory axle shafts. They bend a bit. And the Lockers from the Rubicon 44’s are great untill you go bigger than 33’s. Under load of the 35’s + with 5.13’s the lockers are failing. As are the electronic disconnects. The disconnects are failing because the wheel flex is overclocking the sway bars on the lifted Jeeps. The lifted ones need to run traditional disco’s when wheeling heavy trails. Besides… the links are a major limiting factor on flex anyway. My JK on 33’s out flexed a Rubicon Express Rubicon because he couldn’t get the down travel.

The Jeep/ superlift/ rubicon express engeneers did an awsome job desinging this new JK. 33’s with no lift. 35’s with minor lift. Lots of Mopar parts to lift it under warranty. The ability to walk into your dealership and say… "I want that Jeep over there with x lift and y size tires and wheels. And… Ohh… I’d like to finance the whole thing. " Then the warranty covers the Jeep as it left the dealership. It’s a beautiful thing.


I love your JEEP too… I just have no idea how I would get in it without a step ladder! :blush:

You can get in then… because I carry a step ladder in the back seat. :smiley: