Feeder Stepper Shaking and stuttering

Hi all,

I finished building my kit and I am on to printing some test cubes. I am having some issues with the stepper motor that feeds the hot end. It often stutters and is unable to pull the material properly. It seemed like a simple case of needing to tweak the voltage but if I do, the motor will feed fine except it has a pretty serious rattle (clearly enough that it will not print cleanly) and makes a lot of noise. If I keep turning the voltage screw on the driver, it will cycle between not having enough strength and the stuttering. Its also running very hot. A few other things i've tried:

-I took the feed assembly/Hot end off of it and ran it manually to ensure that nothing was creating too much friction. Same results even without material in it.
-I tried swapping the stepper driver for the spare that is included in the kit.

Any ideas/suggestions would be greatly appreciated. Thanks!

Can you try swapping the stepper motor out with a different one (borrow a x/y axis one for instance) just to rule out a bad motor?

Also are you using a geared extruder or a direct drive, can you post a picture?

I went through tech support and we determined it was a faulty motor. It was direct drive. On a side note, I have been considering upgrading the steppers altogether and was curious to know if the following is compatible out of the box:

[www.amazon.com]

These seem to have pretty good torque.