If you get under the car, look at the front of the tranny. (On the pass side.) There is cable coming out of the tranny and heads up towards the front of the car. This is the short part of the speedo cable(it is a two piece cable.) it is mabey a foot long or so. Unscrew it from the tranny and where it connects with the rest of the cable. Look to see if it is broken. If not you could attach a drill to the long part of the cable and spin it. Have some one sit in the car and tell you if the speedo works. If no I would bet on a bad speedo.