Ok, I am back with an update on my situation. I had gone from the 4" lift to a 6" lift last week, and also installed my 14 bolt in the rear. I had never had any vibrations with my 4" lift, but had really bad vibrations with the new 6" lift. So I changed the shims around 180 degrees, and that seemed to help, but was still bad. Well, yesterday I had my front ARB installed along with 4.56 gears by Drivetrain Direct. They lowered the t-case at the same time and experimented with the shim (took it out, then turned it around, etc). It does drive much better after the lowering of the t-case, but still has a noticeable vibration when getting off the gas at anything over 65 or so...not bad, but you can feel it. So, they had said that a possible cure was to have a custom driveshaft made that uses a "Cadillac style" CV joint at the slip yoke end? Has anyone heard of this before? Supposedly this style CV works with the in and out motion that the slip yoke has to provide. If this is the easiest way to cure it, I would like to do that. I just want it over and done with! Any other suggestions?