For removing it: I filed down the end of a paperclip to make it thin, and then stuck it in into the slot the mute wire was in, towards the middle of the plugs - so the mute wire was closer to the edge. If you look down there you'll see a plastic wedge holding it in place. With the paperclip-wedge blocking that, I shoved another paperclip through the bottom to force the mute wire out.
Also ensure it's in all the way when you move it. I thought I had done it but either it does need a parking brake grounded (I've had the X910, Z130, and now Z150 and the first two were moved mute and parkin