hello, i'm new to this forum and new to CJs and their specifics. I have a  1991 cherokee xj that i really enjoy specially in the snow. but i just found a 1985 cj7 4 cylinder that i like. however, the rear wheels are not turning. to make a long story short i have investigated alot about the cjs and come to the conclussion that the 2 piece axles are shot. so a one piece set is going in i guess. i really like this jeep and so my questions are; i would really like to keep the 4 banger not so much for economy but i will be using it as a daily driver and reliability so..how hard is it to install a set of  quality one piece axles by a backyard mechanic and would you recommend a set. and can i use any drive train parts from the 91 xj and possibly the awesome trans. case. i know for a fact that the 85 cj7 has the wider axles and the 91xj has a dana 35c rear end. i apreciate any info. and i really thank you for taking time to read this. ( i tend to blab alot) any more info you need from me that would help you let me know. again thanks a million.