I have the same issue on mine, It's been there since I bought it a year ago. I've looked everywhere with no luck. I decided to just drive it until something finally gives. It's a real PITA that I cannot find it
1998 4.0 5 speed, Superior super 35 rear, Superior super 30 front, Yukon air lockers x2. 3" Terra Flex suspension lift, 1.25" BL, 1" MML War 8K winch, Dick Cepeck Radial F-C 33/12.5/15.