System developers for four-wheel drive (4WD) drivelines can help to reduce their present high development and investment costs significantly by developing 'standardised' driveline concepts and taking responsibility for the system's layout, design, manufacture, assembly, and validation. Various limited-slip devices to improve traction and handling, and half shafts and propshafts, are available. They need to be integrated into the driveline system, which is then being optimised with respect to system function, endurance, and NVH. During recent years, GKN Automotive has developed the know-how and experience to develop and deliver 4WD drivelines worldwide. A front-wheel drive vehicle has engine, gearbox, front differential, and front driveshafts. In addition, a 4WD vehicle has a centre differential at the gearbox output, or a simple angle-drive gearbox connected to the front differential, and a propshaft to the rear differential, and rear driveshafts, are also required. GKN offers eight important services for 4WD systems. The article also discusses: (1) the power take-off and rear differential; (2) driveshafts; (3) propshafts; (4) traction and handling enhancement; (4) computer simulation and calculation of products and processes; and (5) the GKN test rig and vehicle testing. For the covering abstract see ITRD E107095.