I have a VX Calais 5.7L and my check powertrain light has been on for about a month. I have replace the diff oil and have taken into a mechanic who put on the diagnosis machine and said he couldnt find any faults. I have reset the computer by disconnecting the battery and the only fault with my car that I can find is a damaged tailshaft bearing. I have spoken to a few people who advised me there isn't any sensors on the tailshaft. Can anyone help? the last mechanic charged me $760 and still same problem?