I wouldn't be surprised if the instrument cluster (a.k.a. "integrated meter assembly") is the problem; they had a lot of problems with them in the Gen 1's, especially in the first couple of years. In order to confirm, you would have to pull the cluster and locate the two wires that come from the speed sensor in the harness connector. Then, you can install a multimeter between the wires and put it in AC volt mode. The vehicle speed sensor generates approximately 1-volt (AC) for every 10 MPH. Operate the vehicle in gear with the drive wheels supported or drive vehicle in a safe area and see if the signal is getting to the cluster. If it is, the problem is likely inside the cluster and you will need to send it out for repair. Mr. Whizard is among several companies that can repair them. If the signal is not getting to the cluster, try testing for an output signal at the sensor. If the sensor is generating a signal, then there is an open or short in the harness between the cluster and speed sensor. If the sensor is not generating a signal, it may be faulty, the plastic driven gear may be stripped or damaged, or there is an issue with the drive gear inside the trans.