<VV> Overheating PG - 2nd request

[Ron]

At the convention there was a '61 PG sedan in which the PG transmission would chronically overheat to the point of having a smoking dipstick.  The oil would quickly turn black.  (brown in 100 miles and black in 200)  It seemed to shift and start up just fine but had no kickdown.
Anyone have any clues as to what could cause that?  Current suspicion is on the converter.
RonH
There was no response from the first query on this item.