Try "Hemmings Motor News". Pick up a copy at your local news stand or go on line.
ask.com
On the internet - Google 1984 Dodge D100 PU.
The Haynes manuals have excellent wiring diagrams. A Dodge dealership may be able to order you one also.
Yes. You need a transmission and new front axel. I would just find one with 4x4.
ORieley auyo parts,They sell manuels. Get the one on Electical system.
These diagrams can be easy to find. It is best to look through the users manual or to find an image online.
tcpglobal.com for paint codes, production numbers
Part # 3004 104 or 2864152 or nsn 5930-00-144-4994 you can find some online takes a little time.
Check dormanproducts.com or call your local dealer. If Dorman makes them, you can get them almost anywhere (AutoZone, Advance, Carquest).
autozone.com has wiring diagrams most public libraries have chiltons and or haynes manuals you can copy the pages you need for like 10 cents each
Dial A Clutch, they are national industry supplier, just Google for their web-side.
its the sending unit