what green was saying is that you cannot use z axles on a j30 diff there to long…(which he sold knowing they wouldnt work to me and fucked me outta money hanks paul lol…) and to use a z diff with z axles there are some mods you need to do for it to work…if you have the j30 diff like i have and have the axles from the same j30 it is a direct bolt in