My 1993 500SL/R129 has a speedo and odometer that is not working. But the tach works, as well as the clock on the cluster. My local mechanic is checking the speed sensor (apparently located on the transmission) before we send out the Instrument Cluster for repair by Mr Whizard or BBA-Reman. Has anyone experienced this same/similar issue? My mechanic says that the speed sensor is $500+ just for the part. Is this correct?!