54 hornet hydromatic problem

Just got my hornet on the road and the auto won't pick up the high gears oil level is good has low gear and reverse but won't select up into higher gears and hits neutrals when I fitted the engine and box I accidentally broke the throttle shaft off that goes through the centre of the selector shaft so I couldn't hook up ACC to auto is this the problem or is it the adjustments on top of box has anyone driven one with this disconnected any thoughts ??