Only ONE???? Dang!!!
High pitched could be metal to metal or rubber to metal.
If FWTJ's fix doesn't help, hit all the rubber bushings with some PB Blaster to see if it helps. Then start looking for something loose.
97 Sahara, 74 Renegade, 72 CJ5, 55 Willy's (the Beast) Boss 302, 6:34 gearing, Bose 901 speakers.
God I miss that Jeep. Forgot the kinda Jeep, 80 SX4.