2.7 LITER. Alternator nut. A solid metal or plastic block with a threaded hole in the center which is used to tighten or adjust the Hybrid High Voltage Battery. Alternator Nut. Catalytic Converter Nut. Exhaust Pipe Nut. Hex. Alternator lock. Catalytic Converter. Center. Drive Motor Battery Pack. Exhaust. Spare carrier.