I would go after the double cardan joint at the back end of the front driveshaft, if its 4wd. Any wobble? it should be stiff, and NO play at all, in any direction. I would also change the front ujoint, too, while its off.(pry on it in all directions) also, the axle joints (pry in all directions, as well.) are probably due, once again, if its 4wd. if its 2wd, I'd definately get after the ujoints on the rear axle driveshaft. Please let us know what'cha find!!!That double cardan is rebuildable, but I wouldn't do anything but take the driveshaft off and deliver it to a driveline specialist, if you haven't got a oxy/acytl torch. it consists of 2 ujoints and a ballsocket assy. (I suspect your ballsocket assy is shot) the ballsocket assy comes as its own kit. Again, if it's 4wd. It should be considerably worse in 4wd.