When Driving 1994 Toyota Corolla the speedometer will occassionaly go to zero. When this happens the transmission acts as though it was placed in neutral. The engine will rev, but no transmission. I can take my foot of the pedal, pump it, and then the transmission will reingage but the speedometer remains at zero for another moment or two. Normally the car works fine.

Could this be the transmission speed sensor causing this?

 

[qoute]Could this be the transmission speed sensor causing this? [/qoute]

sounds like it is... have you tried to check if the sensor installed properly???

 

I checked that. I did unplug the sensor and the car runs better, but no speedometer. Do the sensor do anything else?

 

Speed sensor goes to a module in the dash then to speedometer.

If the speed sensor is not working the speedometer will not work.

The speed sensor attaches to the differential which of course attaches to the axles.