I finally have started working on my truck. (1981 K-10, 305ci, T350, 208) I am in the process of getting all of my gauges working, and the only one that is giving me problems is my speedometer. The needle dosn't move when the truck is moving, however when I put a drill on the back of it I got movement. I have replaced the cable, and currently, I am leaning towards the gears in the transfer case being bad. Is there anything else that would cause this problem? If the gears are all that is left, where can I get some replacements? Also Does anyone know what color I would need? I have 4.56 gears, and 36in TSLs. Thanks for any help you might be able to give.