Like many of the rest of you I have a vibration at highway speeds, but it is only really noticable when excelerating in fourth gear. I have replaced the rearend(only 1000 miles on it), transmission, and rebuilt the tcase, chain and all. I have a 700r4/208/10 bolt drivetrain. I have heard before that sometimes the vibration is caused by the slip yoke. How do I tell if the yoke has gone bad, as far as I can tell everything is fine. There are no visible crack in the yoke, or dents in the driveshaft. The splines on the shaft mesh well without much play. It started leaking from the yoke, is this an indication that it is broke somewhere internally. Also could it possible be the front CV joint. I don't think it is because I fragged two u-joints in the rear one after another. I took it as an indication that the vibration is somewhere in the rear driveline, but I could very well be wrong. Thanks for the help in advance.