Popping/strain on turn, 2000 Tahoe

[Purplebeard]

Just picked up a 2000 Tahoe for my wife. Put about 400-500 miles on it so far. Last long drive (about 300 miles), I noticed a very subtle whistling/screaming from the passenger rear end. First suspicion was brake clips (used to warn of low pad depth) as the pitch/intensity would change and/or dissappear depending on the lateral force (right or left tension). I also thought it might be an axle bearing but the brake noise seemed most logical. Just made a 60 mile drive, noticed the noise, not too much thought about it, couldn't hear it with radio on, could notice it when the cabin was quiet though. Didn't seem to affect the coasting/driving/power/control until I reached my driveway. As I turned the corner (left hand) right before my driveway, and as I turned into the driveway (left hand), the rear end (as far as I could tell) made some serious mechanical popping and straining like the wheels were locked and wouldn't "slip" for the turn. Not a pretty sound for sure. I backed out of my driveway, and on the rather tight turns, it would follow suit on the tension. drove about 50 feet with no problems straight line, reversed to my driveway, pulled back in forwards (right turn) and the symptom seemed not as severe. I read a forum post about the possibility of a failing differential. I dropped the lower drain plug on the differential just enough to allow a squirt to drop. looked and smelled normal, no metal bits and not a burned aroma. I removed the right rear tire and discovered that the rear brake system is a disk/drum combo (disk for normal braking, drum for parking brake). The subtle whistle/scream was from the inside disk sheild, rusted, deteriorating and getting flimsey enough to contact the turning disk at higher speeds (>40mph is where it was noticable). I did sense that in reverse out of a parking stall or similar action, it felt like the front wheels were in 4WD (jumping/grabbing) over the past couple of weeks, so I am now terrified that the transmission is going to crap out. The trans fluid feels good, isnt too dark and isn't gritty. I'm not convinced it is the rear bearings. Noticed a tiny bit of left/right play in the axle when I had the disk off and could see the axle seal area. Looked clean, no up/down or front/back play. This further is freakin me out about a posible trans problem.

Any thoughts as to what might be going on? Appreciate any comments or suggestions.

Thanks, Purple.

[SILVERADOSC540]

Sorry I can't help you, but welcome to the forum.

[white cloud]

Do you have the limited slip differential? It will make noise and not be "happy" without the correct fluid.