so my Liberty has picked up an intermittent vibration in the front end, only over 65 mph. its on the highway, only, (the only place i go over 60) . i can feel it in the steering wheel. it does not matter if it in a straight line, or going around a long curve. it just comes and goes as it pleases. i've never had anything like this before. if it was a tire out of balance, it should stay vibrating. the front drive shaft was rebuild (by me) several months ago, and i did peek at it, the boot is still good, so i cant imagine that's bad again. its not slinging grease from either of the axles. has anyone had this happen to them?