Wise advise from gentlegiant...
The problem was from the ball screw became loose. There are 5 screws which bolt the ball screw Nut onto it's housing. 3 of the 5 screw heads were broken and the remaining 2 were loose which explains the .045" slop in the z axis.
I was able to take out the nut housing, extract the broken screws, inspect and then reassemble with new screws. Disconnecting, reconnecting and avoiding the lubrication line was a challenge. But I was able to get it all together. The slop is gone and I believe it's fixed though I'll only be totally sure after a week of machining.
Those ball screws are impressive. Though not in the picture I saw the manufacture was THK. After over 20 years of use and no maintenance the screw and nut are in perfect condition.