gavintwopies,
What you need is a really sharp pair of side cutters and put them on the pin and lever them against the casin it will slowly come out bit by bit! i've done thousands! if they snap you have to drill m out and to do his its a box out job!
the cause for this goin is usually the diff side bearings, you wont usually get any noises, the speedo ill fuctuate then stop workin, by this point it chews the plastic speedo drive! really common mate!! new beaing i think