No it isn't. Not sure how old your Lib is, but any suspension components that fail after 25K should be removed and replaced under warranty.
Edit: Unless of course, you have been thoroughly beating it to death off-road. In which case, yes maybe 25K miles of hard off-road use will use up a suspension. But, we have Liberty field vehicles at my work, and they get used off-road quite a bit, and we have never had any problems with the suspensions (at least not like you describe anyway).
Last edited by SCT100; 11-05-2010 at 10:00 AM..