I have a 2001 Ranger XLT 4x4 with 117000 miles. The steering squeaks horribly. I cannot pinpoint where it is coming from under the chassis but what I can tell you is it does not squeak when I push up and down on the bumper nor when I first start the truck. It only happens when I turn the truck and is most noticable at slower speeds. I suspect it may be the ball joints but would like another opinion.

i assume you have checked the fluid level in the power steering pump and have you checked the serpentine belt that runs the the pump and alternator

To check the ball joints jack the truck up under the lower control arm and grab the wheel at 12 oclock and 6 oclock points and try to move it back and forth. I suspect it is the power steering pump squealing. You may need a new one.