speedo

I have an 89 mustang. The speedometer bounced a couple of times and quit working. I suspected it was the cable. I checked to see if it was engaged at both ends and it is. I checked the speedo gear on the tranny and it seemed fine. Could the actual speedo have gone bad or is there something in the tranny it could be.
 
mine broke right were the clamp holds it under the car....just before it goes into the speed sensor. Both ends were fine but the actual cable broke....could be what happened to yours. Goodluck!