power lock, trac lok, spool etc.

The Detroit unit unlocks when force is applied more to one side than the other. What you did was perfectly normal operation for a Detroit unit.

The Detroit units lock when force is applied to the drive shaft and both tires have an equal amount of traction, that's when the unit locks and it remains locked while power is applied, as in going down the drag strip.

You told the unit to unlock when you grabbed one tire and rotated it. That's the two extremes of a Detroit unit. It is either a spool while locked under power, or an open differential going around turns. It would remain locked around a turn if enough power was applied, but most people don't drive on the street like that. lol