Hi y'all was wonderin if i could have a little help please i am having probs with my speedo not workin most of the time the needle stays there on 0mph but some times it will pop up and work (very rarely though) this is startin to do my head in now as i never know how fast (or slow) i am goin although on the bright side this does keep my milage down

my only concern is that the mrs likes to drive my car and she has a bit of a heavy foot lol and i a bit worried that she gonna end up with a ticket.
Any help would be appreciated i was told that i could be the sensor that goes into the dif is this true and how much would one of these cost
Cheers peeps
Matt