speedometer problem

[70inbville]

My son's 82 c-10 speedo reads right but the odometer is spinning out of control, such as measures 5-6 miles per half mile traveled. The needle Broke and I replaced it with one out of an 86 burb. before replacing the old one was also spinning like mad. I broke the needle cutting the dash to install a din radio. any ideas?? I have tried to reseat the cable thinking that had something to do with it and it felt like it went in correctly but?? Thank in advance.