I have a 1990 dodge 1 ton 2wd pickup.. I want to convert it to 4wd...It is a cab and chassib built truck.. It has a cummins turbo diesel (12 valve I believe) and a 5 speed transmission.. how hard is it to couple/ mount a transfer case?? would it involve putting a different transmission in it?? also, do I have to change the rear axle out when I put in a solid axle in the front end because of gearing differences?? has anyone done the swap and could give me pointers/ hints? Thank you in advance, Anthony