My 98 mazda b3000 w/ 18x,xxxmiles, stick shift, 2wd, had the speedometer stop working. i changed the rear end from a factory rear to an open rear w/ 411's six months ago. recently the clutch started going bad. the speedometer failed before any issues w/ the trans, and after the rear end replacement. i've been told there is a vehicle speed sensor in the rear, but no parts store recognizes it in their system. my tach still works, and my abs light is on. why dont i have a speedometer??