Car is 94 fbody. 4.8l/th400 combo. Trans is rebuilt and new 3000 stall converter w anti ballooning plate. motor is on solid spohn motor mounts. Trying to shake out all the bugs before I add boost.

There is a high pitched sound that I cant identify yet. Sounds like whne I had a t56 when you let the car slow down in gear but higher pitched. Any thoughts or suggestions?