If it was damaged by operating in reverse with OD engaged, when you turn the output flange in either direction, this awfull sound eminates from within the OD.

IF OD is in OD mode in reverse, the output of the OD tries to rotate faster counterclockwise than the output shaft of the tranny while at the same time the Sprague clutch is trying to keep the output and tranny shaft at the same rotational speed. Something gives eventually.

What can happen is the Sprague clutch is installed backwards and nothing goes anywhere. This occurs if the OD case is separated and the Sprague falls out before it is seen in its correct position and reassembly is done without a manual to guide.

If installed correctly, a long screwdriver can only turn the bottom most splines counter clockwise.

Duane