Well, that's a long story! I installed these axles about 6 months before all the first trick reverse pinion custom center sections came on the market. Although I ordered reverse pinion axles from the shop who did the installation, they've admitted they messed up the order with Dynatrac by not specifying reverse in writing and the story goes from there. I didn't make a big fuss over the whole deal, the shop and Dynatrac discounted the axles significantly and in the end they're stout as hell and work great. If I wanted more than the actual 5.5" lift that's on there they might be a problem, but any more than this and I can't get the YJ it in the garage.
Initially we shortened and reused the original front driveshaft which worked fine with the NP231. Then I installed a RE 4.5" lift, which uses 5" shackles. These screwed up the pinion angle along with the caster. Then we installed the Atlas II and had to shorten the front driveshaft even more. The angles involved weren't all that extreme, but the yokes weren't aligned well and it tended to set up an internal rattling in the Atlas in 4wd hi at certain road speeds. I had the caster checked at my local alignment shop and installed 2 degree steel shims in front to get it in spec. Then we installed the CV front driveshaft and a new yoke on the Atlas. Voila, works like a champ.