Speedometer Diagnosis - Help

[chevyaddict]

Is there some EASY way to determine where in the system the problem is regarding a speedometer that isn't working? We replaced the speedocable that goes from that little box in the engine compartment to the tranny a couple of years ago; I can't remember now why we chose that one to replace but it must have been obvious it was bad. (This is the downside to having too many vehicles, can't remember stuff like this). Then the speedo worked for only a short time and now it is not working. I got back underneath there today and everythnig looks fine. I took that one we replaced off and nothing odd, put it back up - no work.

Seems a lot of things could be wrong, the other cable, that little box, the speedometer itself or even the mechanism in the tranny but I hate to just start replacing things to try and find out why. So, didn't know if there was some way to locate the problem for certain. Any advice??

 

[69MyWay]

The gear in the trans is plastic and prone to get worn out.

It only takes a few minutes to remove the trans side of the speedo system and inspect the gear.

 

[Scott81]

What 69 said. The metal cable could also be broken. Remove the cable from the tranny, it's an easy thing to check. Here's directions on how to change gears Speedo gear fix

The reason you may have replaced the other gear is that you might have had the bouncing needle problem, sometimes related to the cruise control transducer being FUBAR.