Added an upgrade kit but alignment is off

Hello All,

I upgraded my 3018 pro with a kit to extend the Y axis. Now I can’t get the platen to align. All the way forward is short (still about 3 inches of platen extended, all the way back the spindle is out past the platen (by about 3 inches. I have taken the Y axis drive screw loose and adjusted but it goes back to the same as it was (too far, not far enough).

Any help will be GREATLY appreciated!

thanks,
Wally (still a newby)