The vehicle may lose vehicle speed signal, which can affect speedometer operation and transmission shift quality. Most often the Vehicle Speed Sensor is faulty, however, at times, the driven gear inside the transmission is at fault. Replace the Vehicle Speed sensor and inspect the driven gear upon sensor removal.Google+
Car Problem Reports
Mercury Topaz Speedometer Operation Affected and Poor Transmission Shift Quality
Mercury Topaz Problem
Speedometer just went dead (while driving up a hill, it just ticked and died), and I'm guessing the problem has something to do with the vehicle speed sensor.How much of a repair would this approximately cost?
Replaced the speed sensor, but the gears still will not shift and speedometer doesn't work.