The 90 Durometer RED Spider Coupling wears out over time (Siemens Drives, model EKK ) and can cause the squealing due to mechanical slop between the motor driving the ball screw and the SCALE
feedback attached to the table.
Looseness causing the noise can be from the Ball Screw Thrust Bearing, the Ball Screw Nut Preload, the loss of tension in the X-axis that has and outboard support
set of Thrust Bearings with a .001" Stretch (Arrow 1000 and up); the motor coupling or the red-spider if applicable.
There have been posts addressing how to look for ball screw / ball nut looseness.
Lack of lubrication to the nut will cause looseness and eventually damage. The Model EKK (yr 2000 mechanical design), and EKT (yr 2002 mechanical design);
did NOT have lubrication line to the ball screw but instead a special oil felt pad lubricator of THK design. You could put grease on the ball groove and slowly feed over it to lubricate it.
You CANNOT use a full synthetic coolant (metal working fluid) that has no soluble cutting oil in it or you will destroy the ball screw nut and linear bearing trucks!
Some of the linear bearing trucks had zerk/alemite grease fittings and can be greased with NLGI-#2 Lithium based grease.