Ok here is my dilemma. I have a 1990 XJ with the 4.0 and automatic. I also have a 1989 XJ that is 2wd but with the 4.0 and a 5 speed. My 1990 is leaking oil at te rear main and it's been replaced. Can't seem to get it to stop leaking so I am wanting to swap motors between the two. What all would I have to buy and would the swap work without any major changes?