Hi there,
You may have a broken speedo cable, there is a round knurled nut that locates the speedo cable into the gearbox at the rear of the box, unscrew this and see if the cable is broken by spinning the inner cable with your fingers and having someone watch the speedo it should flicker, if in doubt a mechanic can test this for you quickly.
Mark (mhpautos)
Monday, August 10th, 2009 AT 9:54 PM