.0055 of play in the z-axis

well after 3 months, i finally have my machine. Overall, i'm pretty
happy with the Grizzly 3102. The main area that I'm unhappy with is
the Z-axis downfeed. The fine adjust seems to take a little more
force to turn than the cracks on the XY table. i'm hoping this will
losen up with some lubrication. the z-axis also has a bit of lash:

Basically, I've got about .0055" of play according to my indicator.
This number was obtained by using the fine feed crank to move the
spindle down mabye 1/2 of the way down. Then, I set the indicator on
a flat portion of the underside where the collet goes. Next, I press
firmly upwards from the same place... And the indicator shows a
little over .005 of movement.

Anyone have any sugestions on how to limit the play between the spur
gear and the rack? It seems to me like .0055 is an issue that needs
to be fixed before I start my CNC conversion.

Anyhow, thanks in advance.
Jake