Took my wife's 02 Liberty for a drive yesterday. I had to run into a store real quick and she opted to stayu in the Jeep and wait. Just as I was getting ready to pull out of the parking spot I started to hear a loud noise from the engine. As soon as i started to drive down the road the noise stopped. Seems to only be at idle speeds. Maybe the fan clutch or an idler pulley? nothing seems to be loose of falling off. doesnt make any difference if its in park or in gear. I do have a stethoscope that i may be able to help pinpoint the location, but it freezing outside right now so i figured I'd see if there are any common problems before i forze my nuggets off

Oh yeah, 3.7, auto, 4wd, about 150K