Jeep TJ Axle Swap With Jeep JK Dana 44 - Jeep JK Urge To MergePosted in How To: Transmission Drivetrain on August 1, 2009 0) (
If you're a Jeep TJ owner with a bit of JK jealousy, you're not alone. There are so many things to like about the new JK. Thing is, there's also a lot to like about the TJ. What if you could integrate some rugged JK components onto your TJ? Now that would be cool, wouldn't it?
Well, that's exactly what the team at Burnsville Off Road in Burnsville, Minnesota, has been doing lately. They've been transplanting JK Rubicon Dana 44 axles into the TJ using their JK-to-TJ Axle Conversion Kit. Why is this a big deal? Well, the JK Rubicon Dana 44 front and rear axles offer a number of upgrades over the TJ Rubicon Dana 44 axles. Hey, not all Dana 44s are the same. In fact, the Dana 44 has been trotted out with a vast number of variations over the years and the Jeep Wrangler Dana 44s are no exception.
Compared to the front TJ Rubicon Dana 44, the JK Rubicon Dana 44 has a larger diameter pinion, more outer axle splines, and larger axle joints. The JK axle is also a high pinion and it offers a knuckle with a 4-inch-higher steering mount so you can bid farewell to that "inverted Y" TJ steering. The rear JK Rubicon Dana 44 bests the TJ Rubicon Dana 44 in pinion diameter, axleshaft spline count, and axletube diameter. In addition, the JK Rubicon Dana 44 axles provide bigger brake rotors and calipers, and they offer electric lockers instead of air-actuated lockers. Taking it a step further, when the JK Rubicon Dana 44 axles are compared to the TJ Dana 30 and the Dana 35C, the improvements are even more dramatic.
We recently had the opportunity to travel to Burnsville Off Road and observe the process of how the Burnsville team converts a pair of JK Rubicon Dana 44 axles for fitment into a TJ. Here's how it works.
1. Here are a few JK Rubicon Dana 44 internals compared to TJ Rubicon Dana 44 internals. As you can see on the left, the JK axleshafts are longer than the TJ axleshafts. This is because the JK axlehousing is 5 inches wider than the TJ housing. We'll cover how that plays into the swap later on. Look closely at the axleshafts and you'll see that the JK axleshaft U-joint is larger than its TJ counterpart. The TJ uses a Spicer 760X and the JK uses a Chrysler-specific joint that is equal to a 1350. The ears on the JK yoke are wider and thicker, too. Further, the JK stub shaft has 30 splines, where the TJ only has 27 splines. On the right, you'll notice that the JK pinion is also larger in diameter.
8. Positioning the new bracketry for welding is the tricky part, because these components must be placed in the correct position and angle. Improper placement or imperfect welding will result in improper fitment and the offending bracket(s) must then be cut off and repositioned. Technician Brian Ament has done scores of these conversions and he made the process look easy. First, he tack-welded the shock mounts and then the spring pads.
12. Here you can see a converted front axle installed in a TJ Unlimited. This particular axle is a Dana 30 out of a JK. Which leads us to another point. The JK-to-TJ Axle Conversion Kit can also be used to fit the JK Dana 30 under a TJ. The conversion is identical. This particular axle was used for a couple of reasons. First, the rig was being converted to a diesel powerplant and the engine management system requires input from the ABS sensors found in the JK axle. Second, the owner wanted to run an ARB Air Locker and the JK Rubicon Dana 44 cannot currently be fitted with any locker other than the factory electric unit. Burnsville owner Dan McKeag says this is due to the design of the carrier bearings.
13. A shorter drag link is required. This vehicle had a drag link that had been cut and sleeved (shown), but the kit now comes with a chrome-moly drag link as standard equipment. When it comes to track bars, a stock JK unit is standard and an adjustable aftermarket unit is optional.
So you're probably wondering what kind of costs are involved for this swap. Well, there are several options. If you're a do-it-yourselfer, you can walk out with a front axle kit for $845. You'll need to add about $50 for the JK pitman arm if your rig is a '97-'02. The bracket kit to fit the rear JK Dana 44 under your TJ is $300. You'll also need to plan to spend approximately $450 each for new driveshafts. If you want to bring a pair of JK axles to the boys at Burnsville, have them remove all of the factory bracketry, and install all of the new bracketry so you can install the axles and steering yourself, plan on approximately $1,495 for the front axle and approximately $650 for the rear axle. Once again, you'll need those driveshaft modifications. If you just want to drop your TJ at Burnsville and have them do all the work so you can drive out with a pair of fully functioning JK Rubicon Dana 44's under your TJ, it'll cost you approximately $4,095 for the front axle and approximately $3,325 for the rear axle. No matter which option you choose, you'll need to plan to procure wheels with the 5 on 5 lug pattern.