It would seem that getting a vehicle up to 30 MPH in reverse so the OD solenoid could engage when the governor contacts close would have hazards that would make accidentally engaging the overdrive way down the list of possibilities!
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!