I am forced to use my gps as my speedometer because mine doesnt work. I bought the car this was and the tranny was previously replaced, there is a noise in the gauge cluster, im assuming from the speedometer cable, both ends are plugged in and tight. Do i just buy a new cable?

 

Disconnect the cable from the transmission and spin the actual cable.
Have somebody sit in the car while you do this.
the speedo needle should jump.

If it doesn't, and the cable is on the back of the cluster properly, then most likely the cable needs to be replaced.