Ok, I'm about at my wits' end with the XJ. I've dropped the t-case and shimmed the rear axle in order to get a better pinion and driveshaft angle on the Jeep. I've rotated, balanced and even swapped sets of tires. I've pulled the front shaft, and tried to pull the rear and drive around (harder to do with the rear since no SYE). I've tightened every suspension bolt there is. I've even checked out the brakes to see if they were round. Still, the vibration persists.
I've put the rear end only up in the air, and put it into drive. The vibration is still present there, which leads me to believe it can be only a few things- the t-case, the driveshaft, the axle, and the tires. I gave it gas with both tires on and off, no change. That basically eliminates the tires. The u-joints are brand new, so that pretty much removes that. The driveshaft angle and pinion angle are much better now than they were, but still the vibe is there. It's flat out driving me insane.
None of this was present prior to this past winter- not even the slightest bit. Now it feels like the damn Jeep is going to shake itself apart. I just can't figure it out. Could I have a bent output shaft in the t-case, or a bent axle or axle shaft? If so, how would this have happened, as I've never wheeled it until just recently (it was all street driven). Is there something obvious I am missing? Yes, I know you are going to say "Get an SYE," but even without it, I can't figure out why the vibe would be there. I don't have one on the TJ, and those angles are far worse than the XJ, but it rides as smooth as a Cadillac. I want to blow the damn thing up...