Quote Originally Posted by DaveB View Post
So the clicking sound is the extruder stepper motor cogging? I wonder if changing that extruder's Vref from ~80 to 127 would have any effect?

Yes it is. I did it by accident yesterday! Put a new shim in for the glass and forgot it was .2mm thinner and the stepper started having a fit when trying to print the first layer. A littel to much "squish" for the first layer!

I think I would start with JF's suggestions first before upping the Vref. Seems to me that might be just trying to force it.