2000 Astro Power Steering Problem

My power steering has excess amount of play that causes me to overcompensate in both directions. Dealer looked and said couldn't adjust because it would only make it worse. Any suggestions on how else to fix problem?
thanks,
quintsrfun

I have replaced all 4 tierods, the idler arms, and shockes, still have play in the front end. Tried adjusting the steering box turned it 1 full turn and nows its better, but still not right.

Not sure what all you have done to correct yours but hopefully someone will have another suggestion.