93 Gt moans when turned left - Posi clutches?

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?

have not checked it - no leaks though - appears to be all original back there. I have never worked on an 8.8 before - is there a removable plug on the pinion side of the case?

Soooo I am suspicious of the clutches - sounds like it huh? The thing is that it works great - both wheels spin under power, no chatter, etc... When I jack it up and spin both wheels - both wheels spin the same direction. When I hold one wheel and try to spin the other - it does not do it easily - I have to muscle it a bit to get it to spin (car in neutral with wheels off ground and e-brake off) but when it does start to move it is smooth feeling - I assume this is normal - could it be I just need to change the differential fluid and add some friction modifier? Oh -- by the way - do you need to add friction modifier to Mobile 1 75w90 FULL SYNTHETIC gear oil? It says nothing about it on the bottle. I have always heard if you want your posi to bite better you should just run regular 90w gear oil with NO friction modifier and it will grab harder but it may make some chattering or odd noises - MAYBE this is what someone did before I bought it???? You think?

Took the plug out - full of fluid - it drained out on the floor for a while and I put in a few onces of friction modifier and took the car for a spin - no noise! I do not know if it did not make noise because it was cold fluid or if this did the trick - I will heat it up tommorrow and see what happens then.

just came back from a drive - let it get to operating temperature - when I first started out there was no noise but as it warmed up the noise started coming back until it was just like it was fully heated up. Now I know it is in the rear and heat related and only when turning left in a fairly tight turn. I guess I should replace the clutches and steels in the differential even though it still hooks up great and lays 2 stripes. I am planning a brand new FMS 3.73 gear install with new axle bearings, carrier bearings, pinion bearing and seal, shims, axle seals, crush sleeve, etc... if I do that I wonder if that will fix the noise? I guess I should do the extra clutch disc set up and try to get a better rear in the process - should I also get a new "S" posi spring while I am at it?