Ok, so i just looked through the faq section, and found this answer to my part of my question.
Non-Disconnect, RS:
This axle first made it’s appearance in early XJs with the advent of the Select-Trac t-case. It does not use a disconnect, so the front driveshaft spins even in 2wd. The early axles came with 260 u-joints or an interesting CV design that tends to be somehwhat fragile. Sometime in the mid-90’s, the switch was made to 297/760 joints. Identical to the disconnect 30, it uses a 7.5” ring gear and 27 spline axles, and is a reverse spiral unit. Max gearing available is 4.88. Differentials and axle shafts are available to upgrade any Dana 30 to 30 spline, but a word of caution, when used in the rocks with aftermarket U-joints (more on this later), the weak link with this setup becomes the ring and pinion. This has to do with the inherent problem with the Dana 30 when used with big tires and low gearing, housing flex. When you apply torque to a pinion shaft, it tries to force the ring gear away from itself, and causing the pinion to ride up the gear teeth of the ring gear. This torque loading flexes the carrier and the housing unless both are stiff enough to resist it. With the Dana 30, the carrier takes a lot of abuse, which is why we see a lot of the 3 piece ARB carriers with broken and backed-out bolts. Eventually all this torque will weaken the ring gear and break teeth off of it or the pinion. Another weak link of this and later axles is the passenger side UCA mount. They fold like a cheap suit when abused. Do yourself a favor and weld a reinforcement plate to the front.
My question now is what makes the 2007 jk dana 30 different where it will take the 5.13s?
