Things may be looking better. Evidently the local driveshaft guy has issues. The original shaft out of my X was retubed by this guy and the vibes were still there, but different- rougher at some points (speed) and smoother at others. I took him the 2nd shaft out of the F250 with the dampener. I asked him to simply cut 3/4 of an inch from the splined part, replace both ujoints and rebalance. When i picked it up, he was emphatic that this driveshaft was perfectly balanced. I put it in and the vibration was so bad beginning at 40 mph that the door glass rattled. Literally. Last night, I took my brother in law for a ride after much ridicule that the driveshaft was NOT the problem. As soon as he rode in it, he was doubting himself. We took it to my garage along with a dial indicator. One of the members here sent me Ford's service section on driveline vibration. It stated to check runout at the front (TC case side) and center part of the driveshaft. It said to replace the driveshaft at anything over .020 runout. My runout at the front was .041 and .049 at the center. the slip yoke had .021 and the rear of the shaft was .021. We jacked up the X and put it on jackstands and ran it up to speed. You can visibly see the driveshaft wobble at low speeds. Found out he cut the 3/4 from the tube and evidently welded it off center. It vibrates so bad the garage floor was vibrating with the X through the jackstands. So, I am looking for a brand new driveshaft. In the meantime, I have the first driveshaft he did in there as it vibrates not nearly as bad. I WILL fix this issue. Bad news is, we will be taking the Jeep on vacation. What a waste.

 

I think you should take a good look at the tailhousing bushing.

 

I did. I even replaced the entire housing with another one with no change. There is a little movement there and I will go there after I replace the driveshaft with a new one that is straight. If I remove the rear driveshaft and drive it, the type of vibration I have with it in there is totally gone. I drove it for a week in front wheel drive. Thanks for the advice.