I have a 2001 Grand Cherokee Laredo 6cyl 4WD with 120000 miles.

Recently, when I am at highway speeds, it seems to try to slip out of Overdrive. The "slip" is very brief, just a second or so, and the RPMs only increase by 200-300. It IS enough to notice though, and makes me wonder if is a sign of more problems to come. The tranny was flushed not long ago, and the issue was unaffected.

Ideas, anyone??

Try adding a bottle of Lucas transmission treatment (there's a variety that specifies that it helps fix transmissions that are slipping).

Tranny flushes seem to do more harm than good after about 100,000 miles. I'm not sure why - I think it has something to do with dislodging particles that later get trapped in the critical parts.

Try the treatment and see if it helps. My tranny was fine until about 160,000 miles. If you've taken good care of it you should get more miles before it needs repair.

Yeah unless the car is relatively new flushing the trans when it isn't done on a regular basis will discombobulate the internals and cause more slipping or worse. That Lucas stuff is seems to help from what I have heard but dont fall for the wal-mart special $.99 crap that will do more harm than good.