This doesn't sound good at all! I'm hearing an occasional grinding sound from somewhere in the drivetrain, sounds like its coming from behind me trans or diff area. I suspect the differential. The sound only happens on low speed tight turns and not even always. I've heard it a few times then last night found I Could reproduce it by entering into a tight turn and giving it a little throttle, kind of like what you might do in a parking lot when you need just a little more momentum to get into a space.
Its a real heart sinking kind of sound.
Its not extremely loud, and the car is driving fine otherwise. What could be going on?
My diff has been questionable lately. Here's a history:
a bit over a year ago I Started to hear thi sound from the back end while making tight turns, sounded like a really low frequency hooting kind of sound. The way I described it was very similar to what the shop manual says is the symptom of low fluid. I know I've had some leaky butt on my C5. So I followed the recomendations, drained and refilled. After the recommended figure 8's to circulate the fluid, sound went away. All was fine for about a year (4000 mi) then the same problem returned. I decided to change the fluid again. This time with the GM stuff right from the dealer ($90!) problem went away, returned a couple weeks later, seems to have gotten louder since, and now this grinding sound! When I changed the fluid, it was clear. Looked new, no contaiminents, no pieces of metal or anything like that. There's no puddle of fluid in the garage under teh diff. My car looks like its had leaky butt but its not leaking fast, casing is greasy but dry.
Any advice? Thanks in advance.

 

The problem being on turns and the fact that fluid changes affect it suggests it is the diff. You can always take it to a transmission specialist and get a diagnosis. They will drive it and let you know. Generally it doesn't cost anything for that.

 

I've had posi rears in cars so tight they'd 'hammer' when you took slow turns, not quite as fast as a pneumatic hammering, but, kinda similar. They were just really hard to overcome (slip). I own a 93 car (not a Vette) that has done it since new, I've never given it much thought. Always thought people could hear it from outside the car but that's not the case. If they could, it would have been embarrassing It warrants looking into, but as said above, if fluid changes things, it sounds like its in the diff. And were it me, I would not worry about it.

 

Best possible answer! I guess I'll just keep an eye on it for now, so far other than some noise the car's driving just fine.

 

Drive train problems are almost always cheaper when problems are diagnosed and fixed early on. I disagree with ignoring it simply because it worked for someone else. Who's to say its the same thing? Call around and get it in for a free diagnosis. Many places offer that because they know they will most likely be getting your business.