Why? Just noticed it yesterday turning into a parking lot at 10 mph with no stereo on. This only occurs when turning LEFT on a fairly tight turn - normal turns in the road it does not do it but turning a corner into a parking lot does it. It sounds like it is coming from the rear end - checked all I could think - all 4 tires not rubbing anything, jacked up rear of car and spun the wheels - no noises, u-joints good, checked the posi function - nice and tight - took a bit of force to make one wheel slip when the other wheel was held firm (this is a 3L27 8.8 rear with 114k and never been serviced that I can tell), I shook the wheels side to side and did notice a little in and out play so I checked lugs - all tight but about 1/16" side to side play still can be felt (clunk felt when shook side to side) I adjusted rear brakes - still does it, sucked out the power steering fluid and added new - same thing, put some Lucas power steering addititive in it - same thing (does not sound like it is coming from the steering but I figured the pump is to blame for most moans). The moan sounds like HMMMMMM through the course of the turn and will get louder if the corner is turned faster. I did not notice it on a twisty road when I was trying to make it do it - only parking lot type turns. It will make the sound with the clutch in or out, in gear or out of gear, brakes applied or not applied, etc... It will also do it going backwards with the steering wheel cut to the left. I am thinking it could be the posi clutches since it has never been serviced back there that I can tell and I can only hear it on a left turn where there would need to be a good bit of differential action going on. Anybody have thoughts?