90 crew cab dually

[87bbcs10]

I have a 90 crew 2wd dually with 454 and 400 trans. I am wanting to convert it to 4x4 i have search the forum already found few threads but most are swapping frames over i want to swap in the axle and keep my stock frame. I haven't found a really good detailed swap that has all the pics and tells all the details on parts and how to do the swap. If anyone can post a link that is well documented and has good instructions on all the info that would be great. Or anyone that has do this that can chime in and guide me though it that has pictures that would be great as well. thanks
Tony