Unless you overfill the transmission enough to keep the pocket bearing where the input and output shafts meet submerged, the pocket bearing runs dry and can seize up. An over-full transmission leaks lube into the bellhousing and soaks the clutch disc with oil. The simple solution is to back the truck onto the tow dolly and let the front wheels do the turning. Just tie a slipknot into a piece of rope around one of the steering wheel spokes, shut the door on both ends and tie a granny knot or two outside the door so the steering is locked. That's how we did it in the wrecker business for a lot of years when we had a long haul tow to do.
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!