Cadillac Repair: transmission/ speedometer, fleetwood brougham, bolt head

Question
I have a 1987 Fleetwood Brougham with rear wheel drive. The speedometer will not work when you are driving the car. While you are driving down the road, if you put the car in neutral and rev the motor the speedometer will then show how fast you are going.As soon as you put the car back in drive the speedometer will quit working again. I've unhooked the cable from the tranny and hooked a drill to the cable and it will make the speedo work, so the cable is good.  The tranny is a metric 200.Any help would be appreciated.Thank You for any suggetions.

 David

Answer
Hi David, That sure is a wierd one. It seems strange that you can spin the speedo cable with a drill and have the needle move yet you have to be in neutral with the vehicle moving and rev the engine to get the needle to move. It doesn't make any sence. The only thing I can suggest is to remove the gear from the trans, a 10mm bolt head and fork clamp holds it in place,  and look at them and see if they are flat across or starting to core out. Make sure the cable fits into the gear and won't spin. If nothing is obvious then you will need to take it to the shop. Bill