Here is my conclusion: I decided to troubleshoot my front driveline vibrations Monday. Before buying adjustable UCA's I wanted to make sure they were actually the solution to the vibes I have been having.

So first I traded my front and rear drive shafts. Unfortunately the vibes remained. This means that having the shaft balanced will not fix the vibrations. I then drove around with the front shaft bolted to the rear and no shaft in the front. There were much less vibrations at highway speeds, but still some minor vibes. So this means I still need to get the front shaft balanced. I also checked the yokes for the front axle and T/C and they did not have any play from side to side.

Next I found a way to extend my front sway bars to the appropriate length for a 5.5" lift as opposed to the 3.5" lift that they were made for. I was hoping that having the correct size sway bars would keep the axle from wrapping and moving the pinion downward thereby causing the vibrations to occur. Unfortunately they didn't help.

Ultimately though it seems I am going to have to get adjustable upper control arms, and get my front shaft balanced to get rid of all the front vibrations. Thanks for all your guys' help and maybe I will update this thread once I get the UCA's put just to confirm.

 

I have access to a lot of cherokee parts in my brother's salvage yard and tried 2 or 3 different front shafts. I had a bad vibration with all of them, take them out and the vibration would leave. I was convinced it was something else but yesterday I had the front shaft balanced. What a difference!! He had to weld 2 different sets of weights on it about the size of a half dollar and 3/4 of an inch thick. I don't know why all the shafts I tried were out but they were.
Don

 

Yea I need to get mine balanced. I will try that out first before getting the uppers. When I put my custom rear shaft that is brand new with no vibes normally up in the front, it vibed pretty badly. So I am pretty convinced the adjustable uca's are gonna be required unfortunately.

 

Balance shaft