Ok, the car in question is a 96 Z28 A4. what I have is a rather annoying and on going problem with a squealing or chirping noise kind of like the noise when a small bearing goes bad or a bad belt, but louder and more metallic. This only happens at operating temps and when it's been at those temps for a bit.It sounds like it's coming from the back of the engine/torque converter,front of transmission. Originally, I discovered the crank was "walking". Replaced the long block. Noise still exists. I've replaced the torque converter(was high mileage anyways) had the transmission apart twice,replacing all the bearings and clutches both times, even though it wasn't needed, but again "just in case" .Even had the crank checked for end play again, the shop insist's its not moving, but it's the same type of noise. Everything on this car is new, to include pulley's, waterpump, alt, etc. what makes it even worse is that aside from this noise, everything runs just fine, no overheating, no shifting issues, I don't see a bunch of metal in the fluids and so forth. some have recommended that I "drive it till it breaks". Pretty bad advice if you ask me. I did attempt to record the noise and post it so I could provide a link, bit i couldn't hear it on the video. right now I'm grasping at straws. I'd really rather not drive it till it breaks, especially considering the money I've already put into it.