gear ratio change


before anybody jumps ahead i was looking for it on the search box but unfortunately there is not a straigh answer and unfortunately i dont realy know how it works. basicaly all i want to know is:

-what is the differential gear ratio (rear and front)
-i am thinking on changing current ones to wider axles so i would like to know wich axles from wich trucks would work perfect
-what gear ratio axles would i need
-how will it affect the engine
-how is going to be the feel of it
-i would like to know everything if possible.

i have a 1986 daihatsu rocky 2.8 diesel, "no turbo", 2765cc,4cyl
4wd, leaf spring all around.

i dont want to change gear box because thats not going to happen at all but thats not my question.

sorry if i sound rude but unfortunately i am looking for a straigh answer from my questions no run around and besides this site is the only on that can answer my questions so i will keep posting the same question until i get an answer because i am ready to start working on my daihatsu.

other things you might want to know is that i dont do hardcore offroad, 70% i am in the city, 20% offroad and 10% high speed around 60 mph. thanks a lot and all this realy helps me with my rocky project.