Shouldn't do as it's separate from the speed measuring part of the instrument. I guess the tiny circlip holding the pressed gear fell off if the whole shaft disappeared south? Yes I can't nicely replace the bezel, that's what Pople did for me. Unfortunately my speedo needs work every 3-4 years so I r&r the bezel myself. Doesn't look too good though. Funny that my tach has never been a problem in 25k miles. Probably will now!! While it's in pieces get him to look at the worm drive shaft from the speedo section to the trip/milometer as they often get loose in their bearings and pop out one end. Needs a small piece of bent tin strap glued over the shaft like a big end cap to stop it coming adrift.Don,t know if ot has any bearing on it, but my trip has fallen out,