Possible causes – Low transmission fluid level– Dirty transmission fluid– Faulty shift solenoid ‘D’ valve– Shift solenoid ‘D’ valve harness or connectors– Shift solenoid ‘D’ valve circuit is open or shorted Tech description There is a factory service bulletin for the 2008 Toyota Tundra: 2008 Toyota Tundra Service Bulletin OBDII Code P0766 When is the…