After my axle swap in my CJ, the rear drive shaft is just too short and wore out. I bought a Cherokee front drive shaft as a donor since it has the same size tube and U-joints as mine. My plans are to cut one yoke off my old one and the CV end off the donor and make one that is the right length. I thought about using the whole Cherokee one with the CV but it's too late as I already set my axle up for the 2 U-joint ends. So my question is how do I measure for the correct length? The new drive shaft has 3" of slip joint, do I center that and go off that for my length? Or would I end up bottoming out or over extending? I'm not sure which way the axle will move the most, in or out (up or down). I've searched and searched and can't seem to find a good answer.