The Dual Range Hydramatic does not have a Park position. Putting the shift lever into the R position with the engine stopped locks the driveshaft. If it's got Park, it's a "Controlled Coupling" transmiission, one that's radically different than a Dual Range, and much less rugged. It does shift smoother, however.

"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!