Sloppy steering couplers are not really rare. Grab the steering couplers lower part with a pair of vice grips to stabilize it. Have someone move the steering wheel back and forth slowly. Your should be able to see if there is any slop in the part quite easily. If there is no slop it probably is in the steering box. Thinking a new coupler is not too pricey for the part if required but have not checked and may be way off. Great you found an indication it might be getting bad.