Extruder stepper motor failure

Hey guys, I ended up just buying Simplify3D and noticed (don't think it's related) that my extruder motor is no longer turning during a print. When I heat up the hotend and manually turn the gears plastic is extruded no problem. When I try to print or command the extruder motor to extrude it simply does not turn and I don't think I'm getting any failure or error messages in the terminal. All the other motors work just fine during a print.

I do notice that I hear a sound coming from the extruder motor when I command it to extrude a very soft whine tone that lasts for the same amount of time it should be extruding.

Things I've tried:
Extrude via Octoprint
Extrude via USB connection to PronterFace
Extrude via USB connection on Simplify3D
Measuring each stepper driver trim pot setting (0.38V Makerfarm i3v 8 inch manual recommends 0.39V)
Measuring the 12V bus from the power supply (11.74V)

If anyone has any ideas of things to try next that would be much appreciated!

fit a new motor ?

That's a great idea curious aardvark! I swapped my Y and extruder motors and what I found was really funny. I had rotated the printer so I could work on the Ramps boards and the new perspective allowed me to see that the extruder motor was turning the shaft.

It was loose set screw on the extruder motor! A quick tightening fixed it, day made. Thanks!!

lol - helping by accident works for me :-)