Y axis binding, please help

Recently moved and setting up my Longmill 30x30. Followed the directions for mounting to my wasteboard to the letter. Calibrated with G-Sender at 100mm and only off by 1mm. Machine jogs on the y-axis fine at precise and normal speeds but binds on the right side if I try to use rapid jog. Does the same when I run outline on a project. I have loosened the screws in the anti-backlash nut all the way to removing the screws altogether. The wheels are adjusted properly too.

Can anyone help me? The frustration level and blood pressure are thru the roof.