Intermittent speedometer

[onny]

Had a flat battery on the weekend and had to replace it. Since then my speedometer is only working intermittently. It sometimes starts working again when I've come to a complete stop and starts moving off again. When it does work its showing the speed I'm traveling correctly.

What I did notice when I turned the key to start the car with the flat battery was that the speedo and rev meter went all the way across the other side of the gauge which doesn't happen with a charged battery???

Could I have loosen a connector / wiring when I was replacing my battery or have I somehow damaged the sensor/speedo? It was working fine before I replaced the battery.

If I need to replace the sensor / speed. Can anyone tell me how much its going to cost?

Many thanks in advance.

[onny]

Is it a bit job to replace the sensor or Speedo. If I need to replace the sensor, does the gearbox need to be dropped to get access to the sensor?