We drop the pan ,change the filter, check for unusual debri, adjust bands and linkage. Flushing without dropping the pan ? How do you know if the Transmission has a problem? How does the Filter get changed? If you reverse Flush where does the filter debri go? Back into the Transmission? What Car Company , domestic or import , shows Flushing in a shop manual as normal transmission service? Better yet check to see what Car companies suggest you do not flush the transmission. ie Honda/Acura.