CPV code 50116400 designates Repair and maintenance services of vehicle transmissions in the Common Procurement Vocabulary (CPV 2008), the EU classification used to describe the subject of public contracts.
50116400 is a leaf code — the most specific level of its branch — so it can be used directly as the main CPV code of a contract notice. If it does not quite fit, check the neighbouring codes under 50116000 (Maintenance and repair services related to specific parts of vehicles).