Wacky speedometer?

I've got this 2002 GMC Sierra 1500 2wd 4.3L that we just replaced the speedometer stepper motor. The speedo will read intermittently now, but look at the video attached. I'm tapping on the dash and it jumps. It jumps with the cluster removed (still plugged in), so I know it's not a cluster issue. Anyone else run into this issue?

Oh, for what it's worth, the stepper motors are not the ones that solder in. Also, the scanner will also read the jump in the needle reading.

https://www.dropbox.com/s/349jotnr8lw5cba/20151030_115248.mp4?dl=0