This is a continuation of a "ball bearings in a tin can" noise I have been getting for a few months now. After a lot of specific conditional tests, I have narrowed it down to a very specific set that point towards the transmission.

1. Never makes noise in Park or Neutral
2. The noise exists ONLY between 600-700 RPM. (550 RPM idle in drive, it goes away. Above 700 RPM it goes away until the RPM falls back down.)

The car generally runs fine. I completely flushed the trans and replaced the filter. I used Mobil 1 ATF. I also did the Corvette Servo.

I did not take notes, but the noise could have first appeared shortly after I did the ATF change. When I first got the car, it did not make this noise.

 

I have exactly the same thing! When putting the auto into 3rd or 2nd it's even getting louder. It's less annoying in D but you can still hear it while driving slow. It sounds like a noisy shifter on a bicycle where the chain is constantly scratching through gears.

Maybe someone can give us a hint. My Auto is shifting good and firm but just makes this annoying noise.

 

I have the same noise and it appeared after my oil and filter change as well

 

This is good. Let's stick together and see if we can't figure this out.

I will be diving down to inspect the flex plate and bolts in the next couple weeks (sorry busy right now) I will report back.

 

Follow up: It was the timing chain and gears they were original and very slack. Replaced and everything quieted up and engine ran a lot better.

 

those transmissions have a govornor? Wow 😳 I never knew that. That’s crazy for real I didn’t know that but have owned so many of them