1994 Cherokee shake/vibration highway speed

My 94 XJ shakes/vibrates at highway speed and I can't seem to figure
out what's going on. I had a similar problem a couple months ago and
replacing the front drive shaft u-joints fixed it but it's happening
again.

I hear a kind of clunking as I speed up and it stops (or I can't hear
it anymore) from the front end and occasionally I hear a sort of
chirping sound also. I rechecked the front shaft u-joints and they
appear to be fine. I recently replaced the wheel hub u-joints. Tires
are about 4 months old and have been rotated and balanced regularly. If
anyone has any ideas or something else I might be able to check I'd
appreciate it. Thanks.

Rob