[Bigdav160]

It's my understanding that the mechanical action of the worm gear, with the recirculating balls and moving of the sector shaft, should all be machined to a tolerance that there isn't any play between them. Is it true that there shouldn't be any play as you transfer the movement of the input shaft through the box and out the sector shaft?

I don't think it is possible to have no play. The input shaft moves the worm via slots. The worm has clearance between it's bearing and the case. There is clearance between the sector and rack. I am sure there is clearance between the balls, worm and gear.