Welcome to the forum Tommy, if you want to use your stock rear axles, which are fine, you will need to go with the TLT steer axle, it bolts up and is the same gear ratio. If that's not an issue there are various options available. Search 1/14 truck on flea bay and you'll get an idea of what's out there, or someone should speak up on here that's used the other axles, I know there's a few. As far as a transfer case there are quite a few options, it just depends on your preference and budget, I had an Axial transmission I wasn't using and it worked great.
Scan the builds in this section, it'll give you an idea of what some of the builders on here have used. There are to many variations to list in one post. Also review the posts in the following section, there are many pages of posts with the information your looking for.
http://www.rctruckandconstruction.co...play.php?f=103
Good luck with your build, post a lot of pictures and we'll be able to help once we see pictures of what your doing if you need it. Your better off using a photo hosting site for the pictures you post here, it works better.