I am putting a trans go shift kit in my 78 bronco c6. It says to tighten the band until you can't turn drive shaft by hand with truck jacked up in neutral. No matter how loose the band is I can't turn it. I dunno if a brake is dragging or what. Can I just unhook drive shaft and adjust it that way?

 

Bar it over and see if you can tell whats dragging. The procedure Transgo uses apparently has some advantages. If you can determine it's a brake, pull the drum and adjust the band.

Additional reading: Adjusting C6 Transmission - FSB Forums