I'm having trouble getting my drive gears for the speedo to engage on my factory 4 speed in my 78 Z28. I've replace the input gear (20 tooth), checked the teeth on the inside of the tranny and made sure that the gear in the tranny is turning appropriately. The whole where the input gear goes in the tail shaft has some wear where the gear rides and I'm wondering if something is missing or maybe my problem starts there? I have an electronic sensor in place of the cable and it is working perfectly from the input gear to the cluster, it really seems like an issue with the gears meshing. Everything worked the first couple of miles after getting the car on the road but then it died and every once in a while will catch.It seems pretty simple but I cant figure out what's going on. I'm really trying to avoid the work of dropping the tail shaft if it's a simple fix. Here is a picture of what the inside looks like.