Installed a rebuilt 4l80e tranny, speedometer doesn't work & shifts hard?

how do you check vss? I checked the connections and everything seems tight. I still have the old tranny, should I remove th speed sensor and install in rebuilt unit?

with a volt meter on a/c voltage scale or a lab scope. Faster the turn of out drive the more a/c voltage it puts out. With a lab scope it senda wave form that intencefies the faster shaft turns.