I have a 200-4R with a 3500 stall behind a mild 468 BBC. Once in a while when it's in drive and I give it enough gas to make it kick itself down a gear or two, it'll let out a nasty shreik, almost like a squealing fan belt from hell, and then it'll stop and continue driving normally.

The other day I was driving about 15mph and I manually shifted it from drive down into 2nd. It let out that crazy shreiking noise and it's not stopping. I limped the car about 1/4 mile home and anytime I start it, the noise comes back.

Any ideas?

Pull the pan, check for any debris/trash, Pull trans fix it.

In case anyone with a similar problem finds this thread later... Turned out to be loose trans to motor bolts and flexplate to converter bolts. Tightened them up an all is well for now.