Got a new speedo cable from chevy classics. I tested it with a drill by hooking up to the speedo head and spinning it at the trans end. If I put forward pressure on the drill it reads fine but when I slack off a little the needle jumps all over and makes lots of noise. When I hook up the cable to the trans and put it in gear (truck is up on stands) the needle won't stay put. It's like it just needs to go in a little farther but I've checked and it's appears to be in the head as far as it can go. any thoughts?
