As every Cherokee off-roader will say, including Rubicon Express, if you are going to lift your XJ more then 2 or 3 inches,
you must modify the drive line. Otherwise serious vibrations or even driveshaft failure may occur. For post '96 XJs, a slip-yoke
eliminator and CV driveshaft such as pictured below are great products (so I hear).
I had my friend help me with this part. Mostly because it had to be done precisely (no room for mistakes), and because there
was cutting involved (the shaft coming out of the transfer case. My friend is a mechanical engineer who is currently working
at UC Davis. He has years of experience and owns a Bronco which has been transformed into an incredible truck (last pic in
photo gallery). It is always great to have someone knowledgable to talk to. Many thanks to him for all his efforts.
Again I'm not going to delve into the process...maybe later.
After test drives (both 4x4 driving and freeway driving) I haven't noticed any vibrations at all. I hope to keep it this
way. : ) I guess this proves the quality of the technology I used.