sounds like the belt is slipping. try tighjtening the belt up. on the 258 it can be tightened by moving the alternator out. other modles/year jeeps use tensioning srews i think.
Sounds like a TJ thing, and the same thing my car does. Try removing the plastic cladding from the column and running without it, see if it still squeeks.
I had a '98 Cherokee.
After I removed the gauge cluster to fix the @#$%^&*(*&^%%$$#
BUZZER I put it all back together but the rubber trim surrounding the steering column got doubled up and I didn't see it until I had the last screw back in.
I never did fix that rubber and whenever it was cold it got stiff and during a turn the steering column would drag against the hard rubber and make a horid sound.
Simple fix first! I had that too. Just spray some silicone lubricant in and around the rubber grommet thing that wraps around the steering column
as it goes through the firewall. SPray a liberal amoubnt on. I did this early
last fall and have not had any noise since.
I have a 97 Sport and I get the same squeak when its cold. Goes away after the car warms up. I just figured it was the plastic that surrounds the steering column. I also test drove a 98 Sahara before I bought the 97. It had the squeak most of time I drove it.