In MY experiences, the "slack" is NOT in the "top side" adjustment, but in the adjustment on the INPUT side of the box, where the steering input is received from the steering column. THAT adjustment is seemingly unknown to many, but is there.
If when you turn the steering wheel, before the wheels turn sideways, you will probably notice that input shaft moves IN AND OUT, THAT is probably where your slack is as that slack happens before any steering linkage starts to move. There is a spec for that clearance, but that is also where wear happens, too. Not an easy wrench-type adjustment, but it takes a special spanner wrench to do it. Maybe even off of the car, too?
At THIS point in time, though, your existing gearbox needs to be rebuilt/remanufactured to replace all worn parts or upgraded to a newer version of a Chrysler Corp steering gear.
As mentioned, the steering coupler also wears with time. Kits to rebuild them exist or possibly new units, too.
In SO many cases, people focus on that "top side" adjustment as the only place to twist on. Without looking further for other places where "slack" can exist, unfortunately.
Regards,
CBODY67